Hello! I have some problems with my old nVidia 7800GTX graphics card (to be precisely it became bad, at least I think so), so I have replaced it with nVidia 8800 GTX. I have thought that new video card will solve this problem, but new graphics card – same issues. I do not know what the cause of this problem is.
Hello! First of all, you have not made mistake because your new video card is better and newer one then your old is. If you have installed new drivers over old ones, you will need to remove drivers and install them again. But if this does not solve problem, I think that you have problem with AGP slot on your motherboard. Maybe you should try to dust it and if that does not help, well, I am afraid that you will need to buy new motherboard because your is finished its useful life.