Troubleshooting CD-ROM Problems  

There are many different uses for CD-ROM drives: You use it to install 
software, listen to music CDs, play games, etc. Because of its versatility, 
it can be tricky to troubleshoot CD-ROM problems, so we made a list of 
common problems and their solutions for you. 

Is the drive properly connected? 

When you have problems accessing the drive and it either shows as not 
available, or does not show up at all, the first thing you should check are 
the physical connections of the drive. Take off the cover and take a look 
at the back of the CD-ROM drive. 

Make sure the drive has power. Then check that the data cable is connected 
properly. If it is an IDE drive, you are probably using a 40-pin ribbon 
cable. This cable has a red line along one side of the cable. This 
indicates location of pin 1 and needs to line up with the pin 1 marking on 
the back of the drive. An easy way to remember this is that the side with 
the red line usually goes next to the power connector. Then make sure that 
the other end of the data cable is plugged into the appropriate controller 
on the motherboard and also has pin 1 lined up correctly. 

Another important thing to check is the jumper(s) on the back of the drive. 
Just like any other IDE device, you can either set it to Master, Slave, or 
Cable Select (CS - rarely used). If you have only one device on this IDE 
channel, then the drive should be set to Master. If you have two devices on 
this IDE channel, then one needs to be set as Master, the other as Slave. 

If this is a SCSI device, first check the cable, then make sure that the 
drive has a unique ID number assigned to it, and that the SCSI chain is 
terminated properly. For more information on configuring SCSI devices 
please take a look at our SCSI tutorial. 

And while you have the cover off, you might as well take a look at the 
sticker on the drive and write down the make and model in case you need it 
later to obtain the correct driver. 

Does your PC recognize the drive? 

Now that you know that the drive is properly connected, put the cover back 
on and power the PC on. Watch carefully on the first screen that appears 
when you do. You should see several lines where the BIOS detects IDE 
devices and displays the devices it found. Is your IDE CD-ROM drive listed 
here? If not, hit the key indicated on the screen to enter the BIOS setup 
menu. The most common keys for this are Del, F1, or F2, depending on the 
BIOS manufacturer. Once you see the setup screen, look for a listing of the 
primary and secondary IDE devices. Again, it varies where this menu is 
located, but it should be easy to find. When you see it, check what each 
one is set to. Each one should be set to Auto, or Auto Detect, which tells 
the BIOS to check for a device on each position on each channel during 
bootup, and try to identify the device automatically. But if it is set to 
None, The BIOS won't even look and therefore cannot find the drive. 

After correcting the setting here, save the changes and exit the BIOS. This 
will automatically reboot the machine. Watch the screen again carefully to 
make sure the drive is now being recognized. If the CD-ROM drive still 
doesn't show up, then you might be dealing with faulty hardware. Replace 
the cable to the drive with another one and see if the problem persists. 
The next logical step would be to swap the CD-ROM drive with another one 
that you know works. This process will help you eliminate the possibility 
of bad hardware. 

If the CD-ROM now shows up in the BIOS, great. The PC knows about it. Let 
the boot process continue to load Windows. Once you're in Windows, open 
Windows Explorer, and see if the CD-ROM drive is now listed and accessible. 
If it doesn't show up, then it's time to look at the device manager. Go to 
Start/Settings/Control Panel/System/Device Manager, and look for an item 
labeled CDROM. If it's there, click on the "+" symbol next to it to expand 
this category. You should now see the drive listed. 

If there is an exclamation mark or red x next to the drive, it indicates 
that Windows has a problem with the drive. Double-click on the description 
for the drive to get to its properties and read the device status for an 
explanation of the problem. For example, Windows might not have a driver 
available for the drive, or the wrong driver was installed. Windows is very 
good about recognizing CD-ROM drives and installing the correct drivers for 
it, but sometimes you need to install the driver manually. 

To resolve such a conflict, first check to see whether the drive was 
identified correctly. Compare the make and model listed in the Device 
Manager with the make and model of the actual drive that you wrote down 
earlier. To update the driver - it either came on a floppy with the drive 
or can be downloaded from the manufacturer's web site - click the Driver 
tab in this Properties window and select Update Driver. Click Next, select 
Display a list of drivers in a specific location ..., click Have Disk, then 
use the Browse button to direct it to the drive and folder where the driver 
is located. Once this is finished, you will be prompted to reboot. When 
Windows is up again, go back to the Device Manager and confirm that the 
problem is now resolved. 

No sound 

Another common problem with CD-ROM drives is that the drive seems to work 
fine when installing software, yet when playing a music CD there is no 
sound. If you have checked the obvious, such as speakers powered on, volume 
up, etc., without success, then you should check the connection between the 
CD-ROM drive and your sound card. Music is not transferred through the 
regular IDE or SCSI data cable, but through a separate cable that connects 
the drive directly to your sound card. If you look at this picture, you'll 
notice this cable on the left. Make sure that your drive does indeed have 
this cable and that it is securely connected to the appropriate port on 
your sound card. If your sound chip is not on a separate sound card in a 
PCI or ISA slot but integrated into your motherboard, then there will be an 
appropriate plug on the motherboard. 

CD-ROM drive letter changed 

Windows usually assigns the first available drive letter after the last 
hard drive partition drive letter. For example, if you have two hard drives 
with two partitions each, the hard drives will be C:, D:, E: and F:, and 
the CD-ROM drive will default to G:. This system is nothing unusual and 
usually works just fine. The problem you can run into later on is when you 
start adding or removing hard drives or partitions. This might cause the 
drive letter assignment for the CD-ROM drive to shift up or down. This can 
cause a problem when you try to use a program that requires its CD in the 
drive while using it. For example, if you want to play a game like Quake or 
Unreal Tournament, you always need to insert the CD first. If the CD is not 
in the drive, you will be prompted. When you install the game (or other 
software), often the application will make a note of the drive letter that 
it was installed from and expect the CD to be available at that drive 
letter in future use. When the drive letter has changed, this won't be the 
case. Some programs will complain about it and ask you to point it to the 
correct location, while others might flat out refuse to work. The tedious 
but safe solution to this problem would be to reinstall any application 
that behaves like that right over itself after a CD-ROM drive letter 
change. This will update the application with the current drive letter. The 
quick but not always successful or safe solution is to use a third-party 
application such as Drive Mapper or Change of Address to search the 
registry and INI files on your hard drive for references to the CD-ROM 
drive letter and update it with the new letter. 

CD-ROM won't read certain disks 

Another common symptoms with older CD-ROM drives is that they seem to be 
extremely picky about what CDs they like. Some CDs it reads just fine, 
while others it has to try several times before it gets it, and yet other 
it refuses to read at all. This is nothing unusual, CDs are not always 
equal, the quality of even store-bought, professionally manufactured CDs 
can vary immensely. Each CD production facility could be using a different 
type or brand of blank CD to manufacture the software, different machinery, 
different tolerance levels, QA procedures, etc. In addition, you can run 
into problems when you try reading a CD-R (recordable, a CD that was 
created with a CD burner), as older CD-ROM drives cannot read them. 

Tweaking CD-ROM drives 

There are a few things you can do to tweak your CD-ROM and its behavior 
that might speed things up a little and get rid of some little annoyances. 

Turn on DMA 

Newer CD-ROM drives support DMA (Direct Memory Access) mode which takes a 
little load off of your CPU. To enable this, go to Start/Settings/Control 
Panel/System/Device Manager, click the "+" symbol next to the CDROM 
category, double-click the entry for the CD-ROm drive and select the 
Settings tab. Check the box for DMA, click OK, and reboot your computer. 
When Windows is back, go back to this dialog and see if the setting stuck. 
If so, the drive supports DMA, and if you don't see any problems, leave it 
enabled. If it unchecked itself again, or you have problems after this 
change, disable this feature again. 

Put the CD-ROM drive on a separate IDE channel 

If you have a regular IDE CD-ROM drive, then you can increase performance 
in certain situation a bit by putting the CD-ROM drive on a separate IDE 
channel. If you were to put both your hard drive and your CD-ROM drive on 
the same primary IDE channel, then you might take a small performance hit 
when doing something that requires both devices to be accessed, such as 
playing a game from CD, playing music CDs while working, or installing 
software. The reason for this is that IDE cannot multitask, it can only 
address one device at a time, meaning that data can be transferred either 
from or to the hard drive or the CD-ROM drive, but not both at the same 
time. By placing the CD-ROM drive on the secondary IDE channel, hard drives 
on the primary IDE channel can be accessed at the same time as the CD-ROM 
drive on the secondary IDE channel. 

Turn on/off auto insert notification 

You've probably noticed that whenever you insert a software CD, the 
installation program on the CD will fire up automatically within a few 
seconds. The same happens when you insert a music CD. Within a few seconds 
the CD player will come up and start playback. This feature is called Auto 
Insert Notification and is enabled by default in Windows. If you want to 
change this behavior, you can do this in two ways. To disable this feature 
on a per-case basis, simply hold down the Shift key on your keyboard when 
closing the CD tray for about 10 seconds. This will prevent automatic 
startup for this one instance. To disable this feature permanently, go to 
Start/Settings/Control Panel/System/Device Manager, click the "+" symbol 
next to the CDROM category, double-click the entry for the CD-ROm drive and 
select the Settings tab. Uncheck the box for Auto Insert Notification, 
click OK, and reboot your machine. For more information on this feature 
check out our article on Auto Insert Notification. 

Modify the Windows CD Source Path 

If your CD-ROM drive letter has changed as explained earlier, one annoyance 
you might run into is that anytime you need to access the Windows 
installation CD to add or remove Windows components or to install a driver, 
Windows will still assume that the CD can be found at the old drive letter 
and you have to change it manually - every single time. This can be easily 
remedied with a little registry tweak. Go to Start/Run, type Regedit and 
hit OK. Drill down to the following registry key: HKEY_LOCAL_MACHINE \ 
Software \ Microsoft \ Windows \ CurrentVersion \ Setup. Highlight the 
Setup key by clicking on it once, then look in the right-hand pane for a 
string called SourcePath. Right-click this string and select Modify. Change 
it to the correct path and exit the registry editor. For example, if your 
CD-ROM drive originally was G:, then the source path probably reads G:
\win98. If your CD-ROM drive letter has changed to H:, then simply change 
the source path to H:\win98. 


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