You obviously have a hardware problem, but there is no way for you to
get focused help with the information you've provided. Here is a link
that will show you what details to include in a newsgroup post:

http://www.dts-l.org/goodpost.htm

In the meantime, here are general hardware troubleshooting steps you can
take to narrow down the cause(s):

http://www.elephantboycomputers.com/page2.html#Hardware_Troubleshooting

Testing hardware failures often involves swapping out suspected parts
with known-good parts. If you can't do the testing yourself and/or are
uncomfortable opening your computer, take the machine to a professional
computer repair shop (not your local equivalent of BigStoreUSA).

Malke