I have 4 CD/DVD DIVES (2 internal, 2 external) on a COMPUTER with XP as the OS.  All are recognize as present in My Computer, but none will recognize any typeof CD or DVD after years of doing so.  BTW: My "A" 3 1/2" floppy reconizes and opens floppy disks.

I have uninstalled and reinstall ed thwm through Device Manager, but no luck.  The only new/different item is I hooked up a tape drive backup device to the printer serial port and attempted to load drivers I had dowloaded from mfgr ste (didn't install).  Tape drive isn't recognized in "My Computer".

Help!Were these Colorado tape drive software or anything from HP by any chance ? ?
Years ago...back in the Win98 days they caused problems with knocking out Windows RECOGNISING CD drives...
At any rate remove the tape drive software and re-boot and see if this changes things.Also, in Device Manager are there any errors listed concerning your optical drives?Thanks, "guys".  It is a Sony Storstation I've had for a number of years.  I have not been able to locate the any software that was installed.  The tape drive was never recognized.  But, I have tought this was the source of my problem as it began right after I attempted to install drivers sent me by Sony (I cannot find my original CD for the tape backup).  Everything CHECKS out OK in Device Manager.

Any ideas where the drivers for the tape drive (serial printer port) would be?  Or, any other ideas?As for your drives, try this:
http://support.microsoft.com/kb/314060
Method 2.Remove the external drives and re-boot twice.
Then go to Device Manager and right click both internal drives and select un-install.
Power down and unhook both internal drives.
Re-boot and power down.
Connect only the master internal CD drive and power up...Windows will automatically re-install it.
Check a few CD's to see all is good.

Repeat the process for each additional drive adding only ONE at a time.No luck with Patio's suggestion of physically removeing CD/DVD connections and uninstalling.  Still "sees' the drive acknowledges whether or not I have inserted a CD or a DVD, but will not read it.  Will say to insert disk or just gives me a blank page.

I haven't tried the Registery edit that was suggested yet.Even though "My Computer" dowesn't tell you anything is there and the "autorun" feature doesn't work when it is a DVD you can open and run the DVD from a DVD Player program.Try Broni's suggestion above first...it may be that the aborted tape drive install has juggled the drive letter designations that the program is used to seeing...
If so it may be as simple as re-installing the program.Thanks, but editing the Registery did not appear to do anything.  The drives know there is disk (change status indicator on My Computer to show CD or DVD is in it).  Like I said before, even though My Computer does't show it, the DVD player will play it.

Any more ides before I take the computer in to The Geeks or somewhere?My Computer will read information off 31/2 in my A drive and off USB memory sticks.Wild guess, but does same thing happen in Windows Explorer?Good question as I had not tried that.  But, yes it does the same thing.What happens when you click on your DVD, or CD drive in Windows Explorer? Anything shows up in right pane? Any error messages?With a left click I get a blank pane.  If I right click, I get the message to put a disk into the drive.