Spec: 550W Dual Fan PSU AMD Xp 2500+ 1.4GHZ 1 stick of 512MB 2 Hard Drives DVD Writer 1 USb Modem Connected PCI Soundcard ATI Sahpphire Radeon 9800 SE 128MB Windows XP SP2 Software relating to VGA: Direct X 9.0C Latest Drivers from ATI Problem: ******** My PC will all of a Sudden Power Off (like someone has removed the power cable from the tower). I bought the Radeon 9800de new toughly 4 weeks ago and had no problems what so ever installing the car and getting the PC up and Running, over this period I have played Doom III and A Half Life 2 Demo, with no problems what so ever. Thursday there I started to run into this problem. I was doing nothing different and the card has not been over clocked. The system powered down and I could not power it backup, I then realised my 350W PSU was goosed. I therefore obtained the 550W PSU, which solved the problem for the duration of the night. I left the PC running overnight and the PC was still running the next again morning. That afternoon I tried to play game and the Computer cut out once more. I then pulled the power plug out for 5 seconds, then re-connected the plug back into the PSU and powered the CP backup. I got as far as my Bootloader, then the PC powered down. This power down no happened sometimes even before i get as far as the bootloader and sometimes later. For now I ave installed a very old voodoo 3dfx PCi card and no problems what so ever and the pc has been running for over a day now. I have also played some 3d games (shocking quality of graphics). What Have I Tried To Resolve this? ********************************** I change the latency of VGA controller to 128 , though this had fixed it as windows did boot up and managed to run for a little while, however as soon as I tried to play a game the PC powered down. Removed all components from Tower only leaving: Motherboard PSU CPU + Fan Memory Radeon Card Primary Hard Disk PC did power up but only to power done within 10-15 seconds. I tried different variations of having as little components installed as possible, at one point I removed the Radeon and the pc as far as I could tell did power up ok. Also please note I am running the PC just now with the old PCI card with no problems. I really need someone’s help here as I am pulling my hair out just a little. I can take the card it back to the shop however, I would like to make sure its not something daft I am doing or missing.