Computer restarts at Windows logo.

[mrjellybean]

Hi all. I built a new computer with the following specs a week ago:
i5-2500k
MSI P67A-G43 (B3) LGA 1155 Intel P67
G Skill 8gb RAM
SAmsung Spinpoint f3
Windows 7 Home Premium 64 bit
Corsair Professional Series 650 W PSU

So my brother was playing a game on the computer when it suddenly restarted. I shut down the computer and restarted it. It boots up and POST's but takes a long time to go to the windows logo where it then begins to restart. After the first boot, however, it does not post, but simply endlessly powers on and off.

If I try manually shut down and restart the computer then it POST's and the whole thing begins again.

I haven't overclocked or anything and it was working completely fine before this. Any ideas as to what the problem can be?

 

[Emerald]

can you get into Safe Mode?

 

[mrjellybean]

Nope. I tried changing the PSU to see if that would change anything, but still the same.

 

[mrjellybean]

Okay so I opened it up and reconnected everything. I found out that there was a standoff that shouldn't have been there. I thought it was shorting out the mobo or something so after taking that out it worked for the whole day today. Now it's starting again.

When I turn it on again it says how the previous overclocking had failed when I never even overclocked it. I set the BIOS to optimized defaults but that doesn't seem to help at all.

The computer will occasionally load up fully and run everything and suddenly shut off again.