Three things tend to affect system performance, regardless of OS.
1: CPU
2: RAM
3: # of programs running
Increase the first two and reduce the third.
I recently purchased a used HP Pavillion which has Windows Vista Home Premium. I am quite new to using Vista and from my observations Vista is quite slow. Does anyone have any tips on how to speed up the OS?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic