Help! Pavillion T3529 not starting. Orange light flashing!

Hi there,

Just hoping that someone can help me. I have an HP Pavillion T3529 desktop and a couple of days ago it just turned itself off and I have not been able to reboot it since.

When I turn the computer on it starts up as normal and goes to the black screen which gives you the options to start in safe mode, last known good config or start windows normally etc etc.

When you then try to progess from here Windows XP starts to open but after about 3 seconds it stops and a no signal input thing appears in the bottom right hand corner. The cycle then starts again, back to the black screen etc etc.

One thing I have noticed is that below the power button on the box there is a small orange light that has started flashing. I have never seen this flash before and cannot find anywhere what it means. It looks like there is a small battery picture above it.

If anyone can help it would be much appreciated!

Thanks