CD/ROM won't read or recognize any discs on Dimension 2400

I have spent a couple days searching forums and find a lot of people with my same problem, but no one with a solution that works.  I think I  may need to buy a new CD/ROM drive, but I am hoping to find a fix I am just not aware of.

I am working on a Dell Dimension 2400
I am running Windows XP Pro
The computer is horribly sluggish and I want to wipe it clean and reload the OS.  But the CD/Rom drive won't read any discs, which makes it impossible to re-load the OS.  

When I put a disc in the drive it tells me to insert a disc, so it doesn't recognize that one is in it at all.

The Device Manager shows the drive as a Sony CD-RW CRX216E____PD01
There are no X or ! in the device manager.  When I check the properties it tells me it is working properly.
I have tried to update drivers, uninstall and reinstall it and it says the same thing, but won't read anything.  
I tried renaming the drive with a new letter.

I did the "Express Test" with the resource disc in the drive and got
error code OFOO:136C
Msg: IDE Device Failed: Blank media or no media is present in optical drive
Test req. media with digital data (resource CD, Installation CD)

I've also taken the cover off, vacuumed out the dust, removed the IDE cable and reconnected it to make sure it wasn't loose.  Checked other cables.

I even tried bringing in a USB external CD/ROM drive to load the OS that way.  But I discovered in BIOS it is impossible to get the computer to start up from an external drive.  When I try to set the boot order to read the "IDE CD-ROM Device" first, it tells me "strike F1 to retry boot, F2 for set up utility"  Striking F1 only causes the message to repeat.  So I am unable to use the drive at all.

HELP!

Is there a way to load the OS from the external drive?  Again, that is my goal.  I could live without the drive working if I could speed up the darn computer.  If not, is my drive a lost cause and do I need to buy a new one or is there some secret fix I still haven't discovered?  Any help you can give me would be so appreciated!!!!