Thanks for the reply. Yeah I have tried it with no battery in and with the adapter already plugged in before I turn it on. It's leading me to think it's some sort of software issue.
You can get into safe mode, so take a look in Event Viewer for errors. Unfortunately, most msgs are very cryptic, but might see something that will help you out. If no joy, I would make your CD drive the 1st boot device (f2 setup) and repair install the OS from Windows CD.