Imac G5 Randomly Going to Sleep


Last night, I was loading music from CDs into iTunes, then onto my iPod using a flat-panel iMac G5. During this procedure, at various times the screen would simply go dark, the fans would briefly race, and then the Mac went to sleep. I would awaken it, and keep going, but it did this several times. I tried rebooting, and also making sure that there were no other programs running, but nothing I did seemed to help. It has 1GB of memory, so that should not be an issue. I am running Tiger, and have done the most recent updates (including the one that dims the sleep light). Any ideas? Do I need to take it in for service?
Thank you in advance.
have you checked the obvious, like the settings for the monitor going dim and the machine going to sleep?

Even though you are doing something with the machine, I believe mouse movement is what determines when the machine will sleep.