To the OP: You have an nForce2 motherboard. That's why you have error 43. The board in incompatible with Windows 7 or Vista because nVidia never made a driver for the CPU to AGP bridge...as you can see in the device manager under system devices. You could try to see if a Windows Update will help, but I really doubt it. (With that error 43, no way you have had Aero.)
To the poster right above me....do the same thing as you've done before, only with the Vista driver so you could have Aero. No modding necessary.