well to ask a few questions, do you get any error reports, what kind of processor, memory, hard drive size and unused space, how long has the OS been operating, what do you do with your computer, do you have a good A/V program and keep it up to date, do you have the windows updates turned on, what games are you playing, and can you reboot the computer or do you have to force the shutdown, and if you restart how long before the problem again