I have been using ZASS during many years and decided yesterday to test ZA Extreme. So I bought a ZA Extreme licens.

The installation went fine. I also had no problem to update the antivirus database and to let ZA search the hard drive after virus.
The problem showed up when I tried to minimize ZA. ZA stopped responding. I tried to shut it down using ctr+alt+del, but without success. Soon the entire pc was not responding. I had to reset the pc.

Broken database? I did a database reset, but it did not solve the problem.
Poor installation file? I uninstalled the ZA with the ZA removal tool and did a manual uninstall to check for left files and registry settings, but ZA still crashed after being installed again.
Software conflict? I used msconfig to turn off all other services and software and reinstalled ZA, but ZA crashed anyway and locked up my pc and forced a reset of it.

My pc is pretty modern. I am using Vista 32 bit. The pc got 4 gigs of ram. CPU: Intel i7 Quad Core.

Any tip?