new XP. pc shuts down after awhile, starts up runs

pc runs awhile, quits (screen goes black) starts up.
runs awhile, quits. starts up . runs, and so on.
It didn't do this when it was win 98,2 days goes.
ANY IDEA
Maybe a file I missed.
Have others had this problem ?
AL

Al, that's a symptom of a Power Supply going flaky. Also, rt click on
MyComputer>select Prop>Advanced>Startup and
Recovery-Settings>Uncheck Automatically Restart. Next time this happens
you will probably get a blue screen with error
message. Post the message here.
"AL" <anonymous@discussions.microsoft.com> wrote in message
news:103601c3fe3a$50e6d810$a601280a@phx.gbl...
>
> pc runs awhile, quits (screen goes black) starts up.
> runs awhile, quits. starts up . runs, and so on.
> It didn't do this when it was win 98,2 days goes.
> ANY IDEA
> Maybe a file I missed.
> Have others had this problem ?
> AL