I had a problem and had to reinstall windows XP SP2. Then when I watched online videos through the likes of Camtasia and other systems I get a chipmunk kind of sounds in the background of the main audio. It is the sound as if another track is running in the background at a faster speed.
Anything played with windows media player or real player is OK also CD/DVD played from my CD/DVD ROM drives.
This problem has only occured since the reinstall.
I have Dell 4700.
Can anyone please help with this problem please?

This looks like it may be your answer.
From the Camtasia support page.
Answer