I tried everything I could! I ran every utility that I have. I checked, rechecked and checked again all of my installed software. I removed everything I could from Startup. I uninstalled anything I didn't need. I freed up space on the hard drive.
Nothing helped. Processor usage stayed up near 100%. Only one thing at a time could work. I even turned off MSE.
I was ready to buy a new laptop, and I still plan to. But I finally found The Culprit!
It was my Creative SoundBlaster Audigy NX External:
After I disconnected it everthing returned to "normal". I won't get another for this system, and will get an express-card version for my next one.