The system:

Vista (plain or SP1, 32 or 64-bits). Geforce 7600GS (Gigabyte brand, 256M, stock cooler or Zalman VF-700Cu, factory clocks). Monitor is a Soyo Topaz S.

Vista has a basic driver for the 7600GS, so it works out of the box (or when you swap it in). If I replace this driver with the recent nVidia drivers, after the install, I get a strange tinge (colours are a little off, and banding seems to occur). This state remains until the MONITOR is power-cycled, and then colours get normal again.

This occurs with many recent driver revisions, and may also occur when the Intel chipset drivers are installed (basically any installer that involves making the screen go blank).

I'd suspect the monitor (because power-cycling the monitor always makes it right) and that it's not a fatal flaw (since it seems to be fixable basically every time), but I'd like to know why it happens. I don't recall if it happens with the HD3650 that replaces it, but it might be because the 3650 uses a different install process (you have to run with generic drivers which do neither Aero nor 1920x1200 until you install the ATI package)