also do you have anti virus & anti spyware running and up to date?
if not install and run some of those - many free ones listed in stickys

How old is your puter?
what operating system? Windows ? XP ? xp pro, vista or other

you could also try system restore back to a time when it was still working good.

If it still is crashing after those you might need to look at possible hardware problems --mother board, CPU, hard drive

or if you have the OS CD you could try a reinstall/repair, but don't try that yet.

something like system mechanic might be a help too -tunes up the whole system
I've used it on 3 of our computers with no troubles-
http://www.download.com/System-Mecha...html?tag=lst-1

even when you uninstall programs most will leave pieces in the system registry - the sys mechanic can clean those out.