Computer Shuts down during startup/while doing anything slightly intense

Ok, I had a problem where my PC shuts down randomly while playing games after low framerate for a minute or two. So I decided to lower the frequency back to its original or lower state (previously overclocked) so I did that with no prevail...I then decided it was a problem with the power supply not giving enough power to the CPU so I upped the voltage, then restarted.. Still didn't help at all, same problem, but when trying to get into the BIOS the system froze at the main BIOS screen and My keyboard would work? So after many, Many attempts at getting to the BIOS I decided to download a Program which i could lower the voltage of the CPU in, so I did that and restarted but now my PC wont
go past the startup screen before shutting down. Its not a constant point in which it shuts down just randomly in startup.

Specs:
8mb Corsair DD3
Gigabyte motherboard
Asus GPU
Intel i5 (originally running at 2.5Ghz I think?

 

Your original symptoms sound more like a heat issue to me.

To get things back to normal I would suggest you clear your CMOS There are a couple of ways to do this. There is usually a jumper on the motherboard which you can short and it will erase you BIOS settings and return to factory defaults. You will need to look in your motherboard manual to locate it.

There is a small watch battery on the motherboard which keeps power supplied to your BIOS when you turn the power off. Remove the battery for 30 sec then put it back in.

NEVER change the voltage unless you are overclocking and fully understand what you are doing as you WILL fry your CPU.

If your PSU is not outputting enough power then it is faulty and needs replacing.

Try resetting then give your system a good clean inside. It doesnt look that old so I am supprised if that is the problem but it is easy as a starter.

 

To check temps while running the PC, download Open Hardware Monitor. This will allow you to view CPU temps in real time and possibly spot issues causing temp. spikes.

If this and Tueur's other tips don't work, I would try a different power supply. I just replaced the PSU in a Dell that was giving me fits by randomly shutting down - the new PSU solved the problem.

 

Hi again, Problem resolved! The problem was due to an over-heating CPU and ****ed Thermal Paste and cooler so I bought a brand new cooler. The original cooler was broken and loose so there was a gap between the CPU and coolers metal plates causing a insulating gap so the cooler did **** all. Once fixed Temps are down to 30 degrees while playing games
Oh and I reset my BIOS like Tueur said so that was very helpful thank you

 

Glad you got it sorted! By the way increasing the voltage on the CPU would actually cause it generate more heat and make the problem worse. Keep voltages at stock.

Happy Gaming!