PC made shrill noise and power light flashed on and off

[kjacobs]

I have a PC that is at least four years old and most things have been replaced except for P/S. Tonight I heard a shrill noise from the PC and the power light flashed off and on regularly like a beacon. It has NEVER done that before. I rebooted and it said to go to Power Mgmt in BIOS. The temp was 75 degrees.

I replaced the CPU about six months ago as well as the fan and heatsink.

Should I be concerned?

Ken