hardware issue

[dep]

this is strange.

this morning my desktop machine just stopped. shut down.

it's an athlon 2.3; i thought that maybe the chip fan had died and 
had therefore shut everything down, but the fan certainly moves 
freely. i can't tell more than that because the switch, which is one 
of those non-switch switches, has no effect in bringing power to the 
machine.

my thought is that i popped a fuse in the power supply, but i can 
find no external fuse socket.

i'm utterly at a loss. informed adice, ill-informed suggestions, and 
anything else would be welcome.
-- 
dep