Parallels won’t start now

I’ve been using Parallels for a few months now. Things have been mostly fine. I successfully downloaded a program for PC called “QAvimator†from their site. I started it for the first time under Parallels Desktop 6. Windows 7 started, QAvimator started. But instantly Windows said there was a problem, it wouldn’t allow the program to start.

The computer froze up. I had to force quit Parallels.
Now,
1. When I restart my Mac – the desktop comes on for a second, then goes back to being a blue screen with the wheel spinning. Then comes back to the desktop, for an instant then back to the desktop. Then it stays on.
2. Next, I can’t open Parallels from the desktop folder. (nothing appears when you click on the folder). I have to go to the Mac Applications folder and start Parallels from there.

I’m not sure what I have to do to stop this from happening.

I have a MacBookPro 5,3 - running OS 10.6.8 – intel core 2 duo – 4 GB memory