Noisy Velociraptor

I have a newly installed 2 day old velociraptor 150gig HDD in my pc and since installation it makes intermittent clicking noises, is this usual?

Sounds like the drive got dropped somewhere along the way.  That clicking noise is caused by one of two things: not enough power, or it’s failing.  If you pull the data cable and it keeps making that sound it could be a power issue.  If it stops making that noise until you connect the data cable, it’s the drive.