Avid Pro Audio Community - PT 7.2cs3 wont open after other programs have run.

Im running a Dual 2 gig PPC G5 with 4 gb of ramm, PT 7.2.cs3 (And yes i installed the correct cs update, NOT the Mac Pro update) on OsX10.4.8

My protools seems to crash if i use any other programs before it. Ex: I turn on computer, and use PT, its fine. but if i turn on my computer, use PT for a bit, quit and use, for example Itunes, the next time i open PT, it wont open. the PT Graphic wont even pop up. It just bounces in the dock for a bit then stops. (oh, and i made sure that the Digi core audio app wasn't open or anything like that.)

Ive tried everything that i can think of just about, Zapped Pramm, Trashed Preferences, Repaired Disk Permissions, I thought it might be a corrupt HD, so i bought 2 new internal hard drives, did a clean install of OSx & PT with the appropriate updates, No dice, Same problem occured. I also, did the same thing on an external fire wire drive, Clean install and booted from Ext Hard Drive. This didn't work either.

Next, I used an entire different G5 in conjunction with the Clean Install External Firewire that i had just setup, to make sure that my interfaces/firewire drive wasn't bad or anything like that. Protools worked fine with other apps all day. (all day during a heavy session at that)

I guess the last thing ill try is to get rid of all the ramm to see if its bad maybe? Does that happen often? Also, maybe i need to repair permissions since ive done all of this installing lately. Can anyone else confirm that repairing permissions needs to be done after an install? I didn't see anything about that on the digi site so far. (ALthough I did try the repair permissions before i did my clean installs)

If there is anything ive left out that you might need to know, or tricks i can try just let me know.

Thanks, Rakestraw