Computer turns off by itself. HELP?

[Lola]

Hi im writing because my computer has beenm acting weird lately. About 3 days ago it just shut off out of no reason. ( i didnt click anything nor downloaded anything that might contain a virus) When i try to turn it on it only gets to the loading Windows part and then it shuts off by itself. About 3 seconds later it turns off by itself and will repeat this same process until i decide to turn it off. I tried turning it on on "safe mode" it loaded fine but after a few seconds with the desktop screen it shuts off and does the same thing. I dont know if its a hardware or software problem. can some one help please?

P.S this message is written by using another computer. not the one that is damaged.

 

[vegasgmc]

Sounds like your processor is overheating or a hardware failure, probably a bad capacitor on the motherboard.

 

[Lola]

Sounds like your processor is overheating or a hardware failure, probably a bad capacitor on the motherboard.

well i tried getting all the dust out of the machine. Also its a pretty new computer (2005) so i dont know if the motherboard is the problem. altho when i turn it on it says "Windows could not start because the following file is missing or corrupt.
\WINDOWS\System32\Config\System"

many friends told me that i had to restart the whole system by installing Windows XP again but i REALLY dont want to lose all my info. i tried loging on safe mode to save it all into a CD but it wouldnt let me log on. it would say the same thing as mentioned above.

 

[Tedster]

replace the PSU with a QUALITY one. read: https://www.techspot.com/vb/topic55506.html

also check your ram with memtest 86+ for at least 7 passes.

I suspect a bad PSU.

 

[Lola]

After a long consideration i dedcided to reinstall Windows XP because frankly i dont think i could do anything else. but now the computer wont read the CD. when i put it it gets to the Licensing Agreement and then it says something like "please insert a windows XP proffesional or home edition and press enter" (those arent the exact words) when this message is displayed the Windows XP proffesional is already inside and i click enter but the same message appears again. i tried formating the computer but when i tried windows after formating it the same thing happened. any suggestions?