HD Native crashing when I change sessions every time.

[Ryan Butler]

So, I started a session this morning and we've been working on this album for 8 days. All of a sudden, it started freezing every time a new song starts loading. I have to force quit pro tools and then I have to shut my computer down by the power button or else it just freezes in the shutoff screen. I've deleted preferences and removed sketchy plug ins. I've unhooked everything hooked up to the computer and plugged it back in after sitting off for an hour. It worked toggling session to session one time after this and then back to freezing. I verified disk permissions on the three drives that are always active during pro tools usage and they all were good to go. The only thing I can think of that I've done differently in the last twenty four hours is shut off my Time Machine Backup early yesterday afternoon.. I turned it back on and same thing. Turned it back off and same thing. I'm running PT HD 9.0.3 with OSX 10.6.3. I'd be grateful for any help.