You haven't provided any information on the problem, the specifics of it, or
the history of it. That's like calling a doctor and saying I don't feel
good, what's the problem? Well it could be the flu or it could be a brain
tumor.
What is the history of this problem, did the system ever work ok? If so
what changed between when it did and now? What is the error message? The
why could be many different reasons. The error message will give more
indication of why. Once you have the BSOD error, then look at his site for
information.