I have a HP a6000n with M2N86-LA motherboard downgraded to XP. I added a 8800 GTS 512mb and it didn't work so I added a 700 watt PSU (it can definately support the 8800 GTS; I know this for a fact) but my screen gets fuzzy and the card does not work. When I use safemode and enter device manager, I can see that the 8800 GTS is there but when I start Windows normally, the problem occurs again. I usually get a black screen or a blue screen with an error "nv4_disp" message. I downloaded the drivers but the moniter turns black or I get a message saying "There was a problem installing this hardware: Video Controller (VGA Compatible) An error occured during the installation of the device Access is denied". I have tried to install the driver, but I can't even download it so it does not work and I have uninstalled the on-board graphics 6150 and it still does not work. Can anyone please help me? Is it the motherboard's fault? How do I "flash" or upgrade my motherboard and BIOS? Thanks.