iMac only boots in Safe Mode

For some reason, my iMac will only boot up in safe mode. If I turn it on without holding the shift key I will get the Apple logo for a few seconds and then the cirlce with a line through it.

Background: We are still running Snow Leopard on this system. We have been having issues at start-up but doing a PRAM reset for 3 chimes always yielded back to normal. Seemed like we had to do this a lot.

I try not to shut it down. I did run the disk utility and after a few minor repairs to the disk the system would boot up fine. But, then again, we don't shut it down often.

Knowing we needed to be on the newer system for security reasons we purchased a new MacBook Pro 13" with dock and 27" monitor to replace the iMac.

So I shut it down the iMac to move it to the other desk as a backup and that is when the system would not start up in normal mode.

I still need to have this computer around to run old software that the new system will not run. Such as Freehand. We have a ton of old designs and files done in freehand.

Things I have tried:

• PRAM reset
• SMC reset

Command R doesn't do anything otherwise I would restore the time machine backup

Holding down option at startup does not do anything but give me the internal disk as a choice.