If your using the theme Vista Aero (with glass effect) then i would recommend you to change the theme to the Vista Basic theme.

The glass effect uses lots of your computers RAM and will slow it down dramatically.

Just found this, it sped up my Vista laptop SIGNIFICANTLY. It’s 2GB RAM, so it should in theory run fast enough. But I had problems with the 2 screen jump to Task Manager (after hitting CTRL+ALT+DELETE) taking nearly 10 seconds), and could never figure out why. Now it’s near instantaneous.

I had no idea that the Vista Aero theme was sucking so much horsepower. Granted the “Basic” theme is a bit less pretty, but I’m sure I’ll get used to it in a few days.