I have had 2 interactions with Ceton Customer Service in past years. My experiences were very positive and they went way beyond extraordinary service.
Case # 1 - XfiniTV 4 channel tuner was damaged due to voltage fluctuations during a storm. Unit was 3 months past warranty deadline. Customer service sent me a new unit for nothing more than the cost of shipping it back to them.
Case #2 - XfiniTV 4 channel tuner stopped recognizing a strong TV signal. Again, very out of warranty. Through the Ceton diagnostic program, they determined that it was a bad board and asked that I send it in for repair. They sent me an email stating that they would not charge me for the repair even though it was out of warranty. And to top that, when I received it, they had exchanged my XfiniTV 4 for a brand new XfiniTV 6 channel tuner at no charge with a nice note saying that they upgraded me because I had that previous problem.
Stalag, sorry you are having difficulty communicating with them, but I will sing their praises always. They are a good and honest company. Their boards are delicate, but they stand behind them.
I am using Windows 7 Professional and my Ceton program and Diagnostics program is very stable. Have you tried uninstalling the total Ceton program and reinstalling it by download directly from their support site to get a clean install?