If it doesn't you need to reopen msconfig and start adding items back one at a time, rebooting after each, until the problem recurs. Then you'll have identified the culprit. However, if the problem DOES recur even with a clean boot, it's either a hardware issue (temperature, ram, hd, etc) or malware.
System idle process shows how much of the cpu is NOT being used. The higher the number the better.