I had the very same problem that occurred once or twice over a one year period 
on a laptop, turned out it was a know problem with my make/model of the 
processor jarring loose.

> Hello,
> 
> I turned my computer on today and nothing happened; the monitor
> stayed blank and the floppy drive light remained on.  The
> computer didn't make any sounds (which was odd, because usually
> the BIOS will when there are severe problems).
> 
> I've unplugged some of the equipment (the hard drive, the
> CD-ROM, the video card, the RAM, etc) in the hopes of making the
> computer at least beep at me; nothing seems to work.
> 
> I'm at a total loss - any ideas?
> 
> Thanks,
> 
> --fission
> 
>