I'm not advertising here, but I have run into a few strange problems with my new CS5 Pre Pro program. Things as strange as main features greyed out (when they weren't that way last load), unable to render, mouse cursor missing. WOW - picky little program that PrePro.
By using a registry cleaner (in this case RegServe), I've actually solved PrePro problems. Not all PrePro problems are fixable by cleaning my registry, but some quirky ones get resolved.
It is likely that other programs and activities in your computer are the cause of the issues you
are experiencing considering your "fix".
Highly likely, yes.
The operating system is as imperfect as the systems it operates (darn - that's almost quotable)