recording problems

hello,

i'm having trouble with sound recording. for a long time,
i was able to record sounds (from microphone and from
computer) just fine. lately, everytime i try to record
something it plays back really scratchy / poppy and too
fast. i've tried using different programs and changing
things in the recording controls but i can't seem to fix
it. i don't even know why it started doing this.

thanks in advance.