1) It will try to load the last file(s) you had open. These files could be "damaged" or missing.
2) I ran into a situation where it could not find the COM port. It is supposed to do this automatically. I switched over to using Win500_Com.exe and that solved the problem. Yeah now I have to manually select the COM port but so what.
What you might try is installing a fresh copy, likely in a new place (directory). Even if you don't install your license, you'll get a 30 day free trial. This will at least see if there is a PC/system issue or just the install you have is running into something.