Hi, I have two video cards 7300 gt and an 8600 gts. My 7300 gt card used to run fine in my gateway PC (AMD X2 4200+, Foxconn C51GU01 motherboard,500 W power supply with 2 12V rails at 18Amp and 16 Amp, 1 PCIE x16 slot, XP Media Center 32 bit) but after I over clocked it using n tune last month it ran fine for a couple of days and then it caused the screen to flicker (horizontal lines) and eventually freeze/hang the system at various time intervals after I booted into the system. Then one day it eventually stopped recognizing the card. I RMA'ed the card thinking that there was some fault in the card and got a replacement for 7300 gt. Also I bought a new 8600 gts card. Before I put the new cards I did a clean install of XP and also updated the BIOS. Also I disabled the onboard n6100 series graphic adapter in the safe mode after uninstalling all nvidia display adapter for it and using a driver sweeper for making sure I removed those. 1. The 7300 gt card was recognized by the system but again started freezing the screen. After this happened I was advised to update AMD processor driver and AMD dual core optimizer and also get NVIDIA beta drivers but they did not help. After that I just went to BIOS and loaded failsafe defaults and then viola it ran for 2 days without a problem but after that it crashed and is not recognized by the system. 2. The 8600 gts card is not even recognized by the system. I can see and hear the fan running when I boot up the system but when I go to device manager it does not even acknowledge the card being there. I also tried to add new hardware but that did not help either. When I did contact EVGA they told me that I might have to reflash my BIOS as older BIOS dont have support for 8000 series car. Now I had already updated with the latest available BIOS from gateway as Foxcon does not support it. Please let me know what else I can do. As this is a micro BTX mother board only gateway keeps a replacement but it is too expensive. I could just buy a socket 939 ATX motherboard and an ATX case and use existing parts which will be a cheaper alternative. But I want to do this only after I make sure it is realy the hardware causing problems not the BIOS. Thanks.