Hardware issues from booting off a eSATA HDD

We currently have external HDD at our college which we use to do labwork with. They work great at school but I would like to be able to do some work at home instead of having to drive out to the labs to finish work. I have an eSATA HDD enclosure set up to boot off my Dell XPS 400 Desktop. But since the Windows Server 2003 OS was setup on the lab computers, the Hardware settings are different and during OS bootup it fails and goes into a never ending restart. Does anyone know how I can fix this problem? Many thanks.