Pro Tools 8 M Powered and M-AUDIO fast track interface problem when recording

[olpolo]

Hello folks,
I'm very new at this and have a frustrating question, hope someone will help:
Here's the situation:
I have
-Pro Tools 8 M Powered
-M Audio Fast Track Ultra
-Windows Vista

I had no problems with the installation since pro tools opens up correctly.
My problem is when I enable the recording button for a track: there is a annoying interference sound. I plugged my guitar to the interface and it sounds clean, but when I try to record in Pro Tools, it sounds distorted and it seems that my speakers are going to blow.
I realize that the input is the problem since when i set the input to "no input" in Pro Tools, I don't get any signal.
Any recommendation?

Please kindly advise.