This is far too litle information for me to hazard any guess.
Did you notice the Forum Tip? It's on the screen with every post you make. It reads -> "If you are asking for help to troubleshoot a computer-related problem, please be sure to include all the necessary information (ie: operating system, model number, hardware, software, etc) that will help others identify your problem for a speedy resolution."
Beyond that, you can try SAFE MODE to get to the Event Viewer to see if Event ID and more tells more.
Also, if the machine is more than a year old (you didn't tell), then remove the case cover, the dust bunnies and until the issue subsides leave to cover off so we get a clue if its heat related.
I need help I have a windows 2000 machince...that once I try to log on to my network it restarts by itself. I went into advance settings and took off the automatic restart option, and I got a blue screen telling me Page_Fault_In_Nonpaged_area...Datestamp 40d1d83-Ntoskrnl.exe...is there anything i can do to correct this issue?