Have you tried to restart and dump the preferences? That can sometimes become corrupt.
On Windows, you hold down Ctrl+Alt+Shift when starting PPro…on a Mac the typical equivalent would be Cmd+Option+Shift I would think, but Todd Kopriva or Kevin Monahan could answer that definitively.
Does it crash whether you launch by double-clicking a project OR if you launch from the application itself (opening a new project)?
If that doesn’t do something…I don’t know how you’ve reinstalled, but uninstalling first is a good way just to clean things up and start fresh…in case something that is corrupt just isn’t being completely over-written.
Upgrading to CS5.5 would help if the preferences for CS5 are shot as CS5.5 will look elsewhere…but that’s a bit like trading in your car when the ashtray is full…
report back on these factors…but any additional details you can think of will be helpful. what were you doing when it last worked? What has been added/subtracted from the system since then? What sort of a project were/are you working on? If you can watch the boot graphic, it will be zipping through some text items as it’s loading (or at least it does on Windows…), if you can see what is the last thing to come up before the app cashes it in…that could be useful.
TimK,
Director, Consultant
Kolb Productions,
Adobe Certified Instructor