OS 10.3.9. Firefox update issue

Longtime Mac user here. Back in the days of OS 9 I used Norton, but since OS X I never bothered getting new virus protection. Frankly, I figured I was playing the numbers since there are so many more viruses made for Windows computers, period.

All of a sudden tonight, I am continuously getting the shut down dialog box -- "Are you sure you want to shut down your computer?" every few minutes for no reason at all.

It makes me worried. I have just downloaded the new version of Firefox tonight, so I thought it might be a bug. I restarted and switched to Safari to see if it would help. No dice.

What do you think? Could it be a preference file conflict (or something like that) from downloading the new software? Do you think it's safe to zap the P-ram? My (Windows-using) boyfriend said that if he feared a virus on his machine he would not reboot for fear it wouldn't start up again, but I've already restarted once without issue...

Has anyone experienced anything like this, or heard of it? I've been googling for a while, and looking on Mozilla's website, but can't find anyone witha similar experience.

Profuse apologies if this is in the wrong section of the forums -- please let me know and I will delete/repost wherever I should. But help/suggestions etc. would really be appreciated. I'm freaking a little.

Panther had a lot of problems with disk permissions that were very easy to mess up : did you launch Apple's Disk Utility, in the Utilities folder, to repair them ?

It could also have something to do with a failing power supply, perhaps. Or maybe you could try resetting the CUDA chip (I have no idea which Mac model you use, but I just found a list of them here, Resetting the power-management chip in your Mac).

You could also try resetting the PRAM just for kicks if the others didn't work.

Report back to let us know how it goes. Good luck !

I did try Disk Utility and resetting the PRAM, but did not know about the CUDA chip. I will try it, thanks!

Not helpful I know, but just to let you know - it won't be a virus.

Are you connected to APC battery backup?

I had the same problem at startup. Drove me nuts. I finally bypassed my APC battery backup and the problem went away. (Of course I don't have backup power now).