I have 2 burners in my computer. One is a DVD burner/reader and the other is a CD burner/reader. At one point drive 1 would burn/no read and drive 2 would burn/no read. The only disc is would read is Command and Conquer Generals: Zero Hour...ONLY! No other non-burnt disc or burnt disc would read. Now they both don't work. I've updated drivers, replaced cables and still nothing. I just recently found out the CMOS battery is low/dead cause I see the message on boot-up. Could that be causing the DVD/CD drives to stop? I have replaced the drives with ones I absolutely know work perfectly and even those don't work.

I doubt that the CMOS battery has anything to do with that, but you can replace it and see what happens. Other steps that you can use for troubleshooting are:
1- Check that the drives are connected properly to the motherboard and power supply unit (highly unlikely, but just in case).
2- Verify that the drives are shown under My Computer and Disk Management.
3- Try the drives in another machine and see if they can work properly (this will tell you for sure whether if they’re working or not).
4- System Restore.
5- Repair or clean install for Windows, but you need a working drive for this.

If you are running Vista you might want to post there, unfortunately I am not experienced in Vista. However, it sounds like a repair-reinstallation of Vista might straighten you out. Also, enter the BIOS and see if your drives are detected.

I've connected and reconnected drives. They are showing up in the computer. They work in my other computer fine and system restore didn't work. The only way I've successfully reinstalled was using boot floppies and then it read the CD. I can't boot from CD (obviously) and even reinstalling didn't work. I've done these at least twice to ensure I didn't miss something.

This is on XP Professional. No SP3 is not installed yet. I can't get Windows Update to download cause the internet connection is not working. Network Connections shows I'm connected but loading pages hangs half-way on the progress bar. Unrelated problem.

The only thing left is to change the CMOS battery and then check if the drives are recognized by the system’s BIOS as ranchhand recommended; if still no joy, then I’d say that the IDE connectors on the motherboard itself are not working.

Will do. Hopefully it works. [crosses fingers]

Are the drives SATA or IDE? If IDE, are they set to Cable Select or Master/Slave?

If IDE and Cable Select, try changing the jumpers to Master/Slave. If that does not work, you may consider setting it to Single and trying one drive at a time. If none of these work, I agree that it is probably the IDE controller on the motherboard. You can pick up a PCI IDE adapter pretty cheap.

The drives are IDE. I changed the jumper setting as told and still nothing. I got a battery and it still didn't work but because of bad and missing files thanks to a virus I had to reinstall Windows. Now they work fine. Thanks for the help. I'll be back if they stop working again.