If this is the wrong forum, let me know and i'll move it

On my computer, powertab has suddenly started acting up. The notes are all the wrong pitches. They're not all equally out of tune, so everything sounds like a complete mess. Some notes are a semitone out of tune, some a tone, etc. I've tried uninstalling it and reinstalling it but to no avail.

Anyone know what's gone wrong or how to fix it?
I had a problem with powertab, it wouldn't play the tabs and it shut down whenever I pressed play. i'd never had the problem before and on reinstallation the problem remained. I was using Vista and found that powertab can be tempermental with it. That's why I asked. Unfortunately I didn't find a solution.