You really have to have some advanced knowledge to be able to use debuggers. Most debuggers are used by software developers to trace problems in software coding. I threw that answer in because that is what the question was. The real answer for most people is to reinstall windows on the computer, usually with the repair option.
Heres a good explanation of what debuggers are.http://en.wikipedia.org/wiki/Debugger
Unless you are into finding why a software acts a certain way, i would not think of using a debugger. You are getting into hacking territory when you start doing this sort of thing. I was messing with debuggers many years ago when i was going to be one of the greatest hackers alive. I did find better things to do with my time, but it was fun for a while.