There is sometimes a situation when Windows suddenly goes crazy: is slow, unresponsive, some things don't work, it crashes. I wonder how do you approach diagnosing those issues.
I'm merely a programmer, not really knowing Windows too deply. There is probably more people like me... I strongly believe that experienced Windows administrators have a bunch of useful tricks that can make diagnosing easier.
Please post your techniques, the more advanced/tricky/unstandard, the better.