Compaq Presario Fan Problem

When ever i boot the PC, I log on and then i get a blank page (this is the xp blue, as this is my wallpaper) and then after around 2-3 minutes the fan (both,the back and the one internal fan) come on.
And it comes on just doing everyday things (Mozilla, Winamp & MSN), also when i shut down my PC i get the 'windows is shutting down...' screen but it does not go off.

I have system restored my PC back to it's old factory issue settings, and this doesn't help. It still comes on. I have not done any mod's to it, it is the desktop version, not the laptop.

I have installed Photoshop,Dreamweaver, MSN and Firefox.

Any Ideas?

The fans coming on is a normal part of the system settings.

and the shutting down thing is most likely that windows has borked it's self beyond repair. the most likely option is to do a complete reinstall to fix it.