I recently shut my system off for several days, and after initial reboot, a high pitched squeal emits. I tried several times shutting system down and restarting, but same result. My computer is slower and this $#@!^!! noise won't go away!! Any suggestions?

Was it a beep? A sequence of beeps? Or just a high pithced squeak?

Hi rino.
"High pitched squeel" is a little vague but you need to isolate the source.
If this "squeel" is coming from the internal speaker on the computer (not your external speakers) and is constant, it's most likely a cpu overheat warning.
I have a feeling, from your description, that the sound is not coming via the internal speaker however.
You're going to have to remove the cover\side and find the source.
Could be a fan, your power supply, almost anything. Dig in.