So after installing Windows Vista, I’ve been getting the following error occassionally: Display Driver Stopped Responding and Has Recovered. Sometimes my system will freeze for a little while then the screen will go black and reappear, sometimes the screen will just go black and come then come back up.

Does anyone know how to solve that problem?

the answer is by lordmeerkat :
I had this problem for quite a long time and nvidia consistently provided a poor response. But I did manage to fix it.

Firstly, ensure you're using the latest WHQL drivers (not beta) from the nvidia website.

Secondly, download and install the latest nvidia system tools. Using these tools allows you to modify the clock speeds.

Be aware that changing clock speeds can dramatically affect system performance, and in some cases actually damage your hardware.

Use the 'Performance' feature within the tools. There will be three clock speeds, core clock, memory clock and shader clock. First, save the profile which you are currently using so you can revert back if you have any problems.

For me, I reduced all the clock speeds by about 1% and the problem went away. For another person who had this problem, they needed to reduce the speed by about 3% before the problem stopped. Note that increasing clock speeds will also increase the frequency of the problem.

Hopefully nvidia will supply a more satisfactory response at some stage in the future, but until then, this is what we're stuck with.