You haven't given us a whole lot of information to help you with.
Can you give us some more details please? The more detailed you are the better we can help. Start with:
what you are doing when the monitor goes blank?
does the monitor ever come back on without a hard reset?
what does the system do when the monitor goes blank?
have you changed anything on your computer lately?
what do you mean by "system doesnt seem to rest?"
Please include your system specs when you answer these questions!