Help with Audacity...

Half the time I can record and half the time it says:

"Error opening sound device. Make sure the project rate is set blah blah." Then I click record again and it works.

Also, if I record like a rhythm guitar track, and then do another track of lead improv, the 2nd track gets delayed or its not synchronized when I play even back, even though I'm recording it on beat, when I play it back it's delayed. I'm using a computer mic (just messing around) and I figured the playback was being picked up by the mic + me playing, so I tried headphones and it made no difference.

Can anyone help?