CPU pegged running at 100%

Greetings:

My computer is exhibiting serious problems.

1) running EXTREMELY slowly ...literally, I watch each individual icon
on my desktop being drawn!
2) pressing any key on the keyboard results in a chirp noises coming
out of the speaker

I pulled up task manager and it shows the CPU pegged at 100%.

No one program is hogging the system. There are a bunch of programs
that alternate at the top slot (ranked by CPU usage). But the top 4 or
5 all avg around 15~20%

The main things is that the SYSTEM IDLE process...which normally is
running at like 99% is ranked dead last at 0%!!!

I tried downloading and running Rootkit Revealer. When I run a scan,
it hangs the system entirely. Not even crtl-alt-del works.

When I tried a system restore, at auto-reboot i get a very weird
screen telling me that my computer is protected by password
authentication. I must supply the admin password and press enter. When
I just press enter, it continues on with the reboot.

Then it goes to a screen that is lablled MANUFACTURER MODE [FF] and
some words about how my computer did an auto-shutdown due to
overheating!!

After this, it proceeds to "windows is starting...." screen and
eventually to the user login screen.....but all the same problems are
still present!!!

Any and all advice GREATLY appreciated!

Thank you!