[CLUE-Tech] bios forcing shutdown?

[Jason S. Friedman]

I'm trying to load a new OS onto my PC.  The PC had a CD
reader, and CD reader/writer, and a hard drive.  I put the
CD in the CD reader and turned on the computer and the
machine ignored the CD and booted the existing OS.  I
turned the machine off, turned it back on, and brought up
the bios menu with the intention of adjusting the setting
that tells bios which device I want to boot from (though I
was surprised it did not read from the CD reader
initially).

I must have adjusted something terribly wrong, because now
when I boot my machine it comes on for a few seconds and
then turns itself off!  I cannot even get to the bios
screen in order to change the settings.