I’ve downloaded the new Audacity version, there was just one long line, another recorder was working, althought with difficulty. I’ve already tried everything! My settings were changed all of a sudden, though I didn’t do that myself. I don’t understand. I have Vista and I obtained the exe. 
See http://manual.audacityteam.org/o/man/faq_recording.html#flatline .
If you still need help after reading everything, please tell us what exactly you are trying to record.
Gale
Do you use Skype? It takes over your sound system and doesn’t always return it to the state it previously had.