It pays to be cautious with Vista, as it is a new platform and not all programs run well on it, even though they may claim to be Vista compliant.
my all new PC on Vista Home Premium was lightning fast for 18 months, or about 2 weeks ago. It would say"not responding" to every program, then would hang there. Any new action took about 5 minutes. Wouldn't shut down etc.
When turned off and restarted, wouldn't start properly-again just hung there. Used the DVD to reboot, but no better.
Took it to a computer shop who had it for a week and said that after they cleaned out a few files it was OK.
And it was-back as new.
Within a few days though it had the same problems. Took me a full day to get it to start properly.
Did a Google search on the problem and found that it was happening identically to others-but none had found a solution.
My thoughts were that there was probably some software that was in conflict, so while it was going I uninstalled quite a few of minor software progs-various things that were supposed to check for problems etc and fix them.
So far so good.
Even the sound card that came with this PC was not compatible, even though it was on Vista only.
So I would suggest great caution in downloading any of the multitude of software programs that claim to be vital to your PC's health. They may be lethal!