I have a similar problem. I bought the Masters version and it was working very well. I used it to record a voice file and converted it to MP3. I then listened to a few cuts on the CD player using RealPlayer. Wavepad was still running but minimized. When I tried to record another file on Wavepad, everything looked normal, but I cannot get it to record anymore. The window pops up normally, but it won't start.
I suspect RealPlayer is the problem. I have re-booted the machine twice, uninstalled and reinstalled Wavepad so far without any success. My next "experiment" is to get rid of RealPlayer, which works well but is a truly loathsome program in how it takes over one's machine.
Have you heard of any conflict problems between Wavepad and RealPlayer?
SS