Is your PSU's fan (or fans) still running? What model is it? What are your system components? Do you have voltage measurements (your BIOS or a program like SpeedFan should tell you) ? Did you install anything new recently that might have exceeded its capacity? More information is needed, but it would be easy to conclude that your safest move is to replace that PSU.
Well the fan is still running, the psu model is DR-B500E (!?!?!)
My system is : PentiumD-2.66, 1 GB ram, Geforce 7300 LE, Hitachi 160GB Sata2, ASROCK 775i945GZ, Samsung DVD-RW. I didnt install nothing lately, on the contrary, i removed my old ATA-IDE HD.
I found that PSU, it's a "Mirage," and seems to cost anywhere from $55-
$80. One would hope the quality isn't too horrendous at that price, but it only has 18A on its single 12+ rail, and also appears to be overrated. I found specs on a Google cached page at: QSsZweXEXIJ:www.techsunny.com/.sc/ms/dd/Power%2520Supplies/1656/MIRAGE%2520ACPS-ATX500W-6%2520ATX%2520500W%2520Aluminum%2520W%255E2FLED%2520Light%25202%2520Fan+DR-B500E&hl=en&ct=clnk&cd=15&gl=us&lr=lang_en" rel="nofollow" target="_blank">http://184.108.40.206/search?q=cache QSsZweXEXIJ:www.t...
It also only has a 20 pin power connector. How old is it? It looks dubious.