Many thanks, BDAqua, for the helpful suggestion.
I did Safe Boot, saw many Permissions Repaired, but no fix for my problem. Here's the problem more specifically:
Computer:
iMac, OS 10.6.8, Windows XP Home in Bootcamp, later installed Parallels 6. Everything works with all the numerous PC programs I have with one exception and that is a audio spectrum program called SuperSID. It is for showing spectra from 0 to 100 kHz and is used for viewing low frequency radio stations for the purpose of observing SIDs (Sudden Ionospheric Disturbances). Signals to be examined are introduced at the audio Line input.
The problem:
The computer lets me look at only the lower half of the spectrum, euggesting the Sample Rate is set to 48 kHz. Windows XP has no means that I can find for changing the SR. Audio MIDI Support in the Mac has a pull-down menu that lets me change the SR, but the change fails to actually take place. I can change the Setting, but it doesn't really change anything. That's the problem.
I need to be able to see the entire spectrum for 0 to 100 kHz. With this more complete description of the problem, can you see any way to let me do that?
Robert