Boot Camp Troubles

Hi,

I'm sorry if this has been gone over before, I tried to search and could not come up with anything specific to what I need.

I have a Boot camp partition set up with Vista on my HD. I've set up Parallels build 5160, and within it have based my Virtual Machine based from the Boot Camp partition. The vista partition works fine when booted to directly, but when starting the Virtual Machine it halts an tells me than there is no operating system installed on the virtual machine.

Could anyone help me out?
Very much appreciated,
Will