Help!

My computer has gone nuts. Like I said, my laptop has decided to turn itself off anytime it's not plugged in, regardless of whether the screen is flipped up or not. What's going on??!?

Also discovered that my Firefox decided to act like it's never been used until today. GAH. Luckily I have my favorites backed up on a separate disk, but they were also in my IE so I just imported them after upgrading to Firefox 3. Is this a virus or something? Because my Norton says everything is fine but I am so confused.

Anyone have any suggestions as to how to stop my laptop from turning off for no good reason? I've changed the monitor power settings multiple times but it seems to have no effect.

If anyone on my flist can help, I'll love you forever...