The usual Get Out Of Jail card is to reset Audacity to 44100, 16-bit, Stereo in Audacity Preferences. Restart Audacity.
Then go into Windows Control Panels and make sure they're set to deliver the right sound device to Audacity. Audacity is a complete slave to what Windows is doing. Are you trying to record YouTube or other internet sound?
Missed one. You should stop using Audacity 1.2.
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Audacity 1.2 is very old and no longer supported,
patched, corrected, or updated. Audacity 1.2 can
be unstable on newer computers.
Download and install the latest Audacity 1.3 from here...
http://audacityteam.org/download/
You can install both audacity 1.2 and Audacity 1.3 on
the same computer, but only use one at a time.
Audacity 1.2 will not open projects made on Audacity 1.3.
If you use MP3 or some of the more modern audio
compression formats, get Lame and FFMpeg software
from the same web site. Do not use older software
or software from other web sites, even though they
may have the same names.
Koz