It sounds like the beginnings of the nasty hack this iMac got hit by via an email link...
It would be a good idea to run an updated version of "VirusBarrier"...
Caution: The VB trial is mostly nonfunctional... but in conjunction with NortonAVS running symultaneous, VB might delete a virus... till the VB trial selfdestructs after expirey...
Also it would be Wise to keep a Disk Warrior on hand... just incase your glitch goes full blown like the one did in this Mac...
Best to file all your valuables onto floppy ASAP.. and maybe make CD copies of your precious softwares and downloads...
I found that a saved CD of the OS Update is often a cure-all to various glitches... usually caused by loading and unloading various bits of poorly written programs...
They way I see it, if you're experiencing nasty little glitches now, it be time to get yourself prepared with the right tools, and the right knowhow fix-it knowlege and data... so you'll be ready for when the shid really hits the fan, and your cumpooder's dead in the water... forcing you back to the dark ages, licking postage stamps, and watching soaps on der teevee...
It would be nice if this forum had a spellcheck...
