Once in a while I go into msconfig (start, run, type msconfig) and startup tab.. then uncheck things like quicktime, camera software, itunes, MSN etc, etc. Basically all unnecessary stuff.

Basically the pc over time gathers loads of progs to startup at PC boot and has them there ready in the background, just uncheck them. They'll still work when you want them to but just wont clog the pc up when you don't.

Like someone said you can google the names and see if you need them to run.