Something wrong with my pc?

[walker2009]

Lo all,
i have recently installed a dvd rom drive in my pc and changed old flat ide cables to round ones!
but now when i try to run 3d mark 2003 or play a game it crashes and comes up with

windows had recovered from serious error occured

BCCode: ea BCP1;81368630 BCP2:814F92F0 BCP3:8143766B0
BCP4:00000001 OSVer:5_1_2600 SP:1_0 Product:256_1

Technical info C\\widdows\minidump\mini030930-04.dmp
c:\\docume~1\davidw~1\locals~1\temp\wer2.tmp.dir00\sysdata.xml

and

Microsoft windows detected a possible device failure.

szAppName: Drivers.Display SzAppVer: 10024E440040121458
szModName:ati"dvag.dll szModVer6.14.1.6292 offset:F06606EA

Technical info C\WINDOWS\logfiles\watchdog\030309_1541_01.wdl


I have no problems going on the internet,

at first i thought it might be the gpu so i re installed old rivers with no avail!
i have also tried system restore to an earlier date also which didnt work either!

I have plugged the cd rom and dvd rom into ide 2 and the hard drive into ide 1, and have also sorted the master and slave jumpers on the drives,
I have double checked i have no loosened any plugs on the mobo.
Im out of ideas what it could b?

My pc runs fine until i try a game etc,

any help welcome!
Cheers
Spec is in sig

400w psu