Power light flashing

[fireflybob]

My PC is working perfectly expect the Power (green) light has started flashing about every 15 seconds for a period of about 5 seconds. At the same time whilst it is flashing there is a constant tone coming from the "tower".

Cannot find anything in the manual about what seems to be some sort of warning. Any ideas?

I have done the usual Scandisk/Defrag/Reboot etc.

[malanda]

What BIOS do you have? (It will tell you when you first power on the machine). I'd suggest having a look on the BIOS writer's website.