Help!! Drive trouble.

I`ve nearly given up on a solution to this problem then I came across your site...

Here goes..I bought my PC from new in 2002,its XP Home edition,service pk 2.

Problem free basically from then until a couple of months ago when I tried to burn a disc,all my PC turned off like in power failure.It would come back on but go through the total disc check thing.Providing I didn`t try to burn a disc,it would play anything from the drive but trying to burn anything and power shut down again.

I took the PC for repair and was told after 3 days there was nothing wrong with it!!I plugged it back in at home and it did the same thing.i was told to take the hard drive back in and show him what was happening.I did this and over the next few days he changed the dvd rewriter etc etc.When I rang he said he couldn`t find out what was causing the problem.

I thought as I can get on the net and still watch films etc I`ll make do as I was intending getting a new desk top PC anyway..Well the draws open but thats it.Only my removable drives are showing up in My Computer they aren`t anywhere to be found in device manager or anywhere else.When I rang back to tell the bloke he said he hadn`t come across a problem like mine and to take it back!!I was to peed off to take it back.It worked better before I took it in!!!

It is now coming up ATAPI INCOMPATIBLE...I`m at a loss what else to do.I`ve checked he put the ribbins etc back,there is power to the drives,a disk will turn in it..

Info on PC is:
Time Computers..AMD Athlon(tm)XP 2600+
2.09 GHZ 1.00GB of Ram
Fat 32 System
Used space 97.3GB Free space 49.3GB
Only drives showing in Device manager are:
IN-WIN IAPP CF USB Device
MS USB Device
SM USB Divice
MMC/SD USB Device
and ST 3160021A

Lower down it says:
IDE ATA/ATAPI Controllers
Primary IDE Channel
Secondary IDE Channel
VIA Bus master IDE Controller

I was told to delete the Primary and secondary controllers and reboot.I did and it didn`t make any difference.My drives should be DVD Multi Recorder and DVD Rom..

Sorry this question is so long but I`m pulling my hair out here.Any help much appreciated.
Thankyou.Paul Hurst.