Bad background noise in audacity while recording

I was recording yesterday and it was perfectly fine. but today i dont know why there is this bad background noise while recording. I tried doing everything i can but I am a newbie so please help me on how I can fix this
here is the sample background noise
https://drive.google.com/file/d/0B2LxG0pvYLxxdHo2cGRuekJaM00/edit?usp=sharing

Thank You
Rajesh

Recording from what? A USB microphone?
As well as the noise, does it also record whatever it is that you are trying to record? If it does, could you post a sample that includes some of that.