Pc starts then shuts down

[tellis]

Hello,
i have a really annoying problem. Sometimes when i start the pc it turns off after 5-10 seconds and then it turns on again..(this happens until i close the PSU).if i unplug the ram,open the pc, close it and then put it back then the problem is solved.(but not forever).do you think its a mobo problem?

 

[Xttony]

Do you have dual bios? Are all the ram cards you installed have same settings?
Reset the bios settings from the bios menu itself.
Your CMOS battery may be dead change it.

 

[tellis]

I don't have dual bios and i have only one ram stick of 4gb....when this problem happens i cant go to bios settings because PC restarts very fast and the monitor doesn't show anything...I don't think the battery is dead because the problem isn't permanent. For example today i couldn't open the PC but when i changed the ram and unplugged the battery the problem was gone....

 

[Xttony]

When you don't have the problem, that is after you remove and reinstall the ram card, go to bios and reset it from there.