PC restarting again and again

[haseebbutt10]

I have Intel Motherboard DG43NB and processor C2Q 8200, OS is vista 64 bit sp2...
when i start my computer after some time (like after 2-3 hours), it runs till home screen of vista and then a restart
and after that restarting gets random...

and it stops after several restarts (probably 4-5 times)

where is the problem?

 

[ghnader hsmithot]

Do you get bluescreeens during restart?

 

[haseebbutt10]

No, just a simple usual restart...

 

[pjmelect]

There could be a number of causes of this behaviour such as faulty memory, faulty power supply, overheating, viruses etc. You will have to do the normal tests in situations like these, run memtest86 overnight, substitute the power supply, check all vents and heatsinks for dust, run Malwarebytes (free version) to check for viruses.
If you have done all of the above then ask for further suggestions.