I have upgraded to Creo 3.0, and as soon as I open files in Assembly, the entire software crashes. I have tried to uninstall and reinstall Creo a few times, but the same problem occurs. Any ideas on how to fix this?
It's not a normal problem. Your best bet is to submit a tech support ticket to PTC. They will want to your files for testing.
As Stephen mentioned, submit a case for Tech. Support and if possible upload the data to case with steps to reproduce the exit.
Make sure the graphics card is running current drivers and is supported. If you are running at 4k resolution, even with good graphics and computer hardware, that might also be an issue, I have experienced that.