There are a whole host of reasons why this could be happening- virus, bad power supply, overheating.... the list goes on.
If you're asking for technical help, please be sure to include all your system info, including operating system, model number, and any other specifics related to the problem.
Windows Outreach Team
i have a HP pc the computer will shut down while i'm working on it with out any notice and i have to turn it back on and let it load back up . sometimes it wont do it for a week and then sometimes it will do it several times a day. I think it's due to over heating, any one know if I can get good software to tell me what my computer temperature is? would there be any other reasons why my computer would be shutting down?