[BScout]

Sounds like your audio interface is being used by something other than Pro Tools (most likely the operating system.) Make sure all system sounds and other computer sounds (iTunes, Web Browsers/You Tube) do not use the same audio interface as what Pro Tools is using. Pro Tools does not like to share.

Go to Windows' Sound control panel and set playback and recording tabs to use anything other than the audio interface you are using with pro tools.

Also, you have not mentioned anything about what your sound card/audio interface is. Might want to do that if you want help since no one on a forum can guess that.