My PC restarts everytime

[Maxwell]

you guys really get that much dust...

wow...

Dust the house -_-

[Grant]

LMAO^

Seriously though, either your Processor has something seriously wrong with it, or it may not be set into its socket properly.  Or, your hard drive may have bad sectors.  This mainly would mean that the computer would constantly hang after a short period of time after being turned on.  The fact that it's rebooting is quite confusing though.  Most likely you have a problem where your GFX card may be demanding too much power from your PSU which could result in the rest of the system restarting as it's not recieving sufficiant power.  Mind giving me some of your system specs please?  It would help alot in troubleshooting your problem.

[Maxwell]

Seriously though, either your Processor has something seriously wrong with it, or it may not be set into its socket properly.

if your processor is not set right your PC will not boot at all...

however it is possible that he may not be getting enough power to his video card, i don't think that would restart it though.

[Grant]

You're more than right about the processor problem, i was only being optimistic.  But a lack of power to the graphics card when it requires it would cause for a restart as the rest of the machine gives up the will to go on.  Therefore everytime the GFX card requires more power than normal it would cause the machine to shut down and restart.