I'm a fairly strong computer literate user, and I recently upgraded my system with an NVidia 6600 GT graphics card. This was self installed and worked well for about a month untill it just started to stop working correctly. One day I play whatever game I want, and it runs fine, the next and until this point whenever I load up any game, be it Dungeon Siege II, Age of Mythology, Call of Duty 2, I will get a strange garbled flashing behind my regular display. In Dungeon Siege it appears only in the initial menu screen where everything flickers and will occasionally flash out of perspective. In Call of Duty I only get it when I get in-game whern I get flashes and streaking from the centre of my screen and it appears like texture models flash black from beneath objects. This problem is universal and occured withing a single day. I updated the drivers and there was no change. I haven't ruled out that it could be something other than the hardware, like a display setting that was changed for some reason, but I don't know.
My computer specs are as follows:
AMD Athlon 64bit Processor 3000+
Windows XP Service Pack 2
NVidia 6600 GT 128Mb grapgics card
Maxtor 160Gb HD
Asus K8NS Pro motherboard
Obviously any help will be appreciated