Possible problem with motherboard

Hello all, i was wondering whether you guys could give me some advice.

I recently left my computer on, unattended for a short period of time. When i returned, the power light remained on,there was no sound from the fans and the monitor was blank. When i unplugged it then, turned it on again (after i had plugged it in ) the power light came on, but there was not a sound from the computer (fans etc.)

My fan had been making a noise prior to that, and i was wondering if it would be possible for the fan to break down and then somehow effect the motherboard?

I am completely stumped and am not sure where to begin looking or testing.

Suggestions and advice will be much appreciated,

Thanks Al

Did you mean not even any noise from the hard disk drive and floppy drive during power up? Any beep code as well? To check if your CPU is working or not, just let your system runs for a few minutes (or less than a minute if the CPU fan is dead) and then shutdown. The CPU should be warm to touch. I can't think of what else to check... let's see, maybe your PSU has gone bad?