I've got an interesting situation I'm trying to work out.
I recently made a deployable Windows 7 pro system image using WinPE, Sysprep, and Answer files. Everything has worked as expected but I'm running into one problem. Once the system is deployed, the main hard drive maps itself twice, once as C: and once as Z:. They are not separate partitions, and both point to the same directories and files.
Z: does not show up as a drive in disk manager, and can be removed with CMD tools, but usually reappears on a reboot. The problem is that User's folders are mapped to Z: through GPO, so I can't have this ghost drive showing up and intruding.
I've had this problem once before on a system installed from scratch using Dell re-installation media so I'm thinking that is related to the problem. I've noticed that the system keeps the Dell theme as the default even when a new default profile is created, so perhaps there are some hidden policies or scripts running that are trying to map Dell recovery partitions or keep the system as "Dell-like" as possible. Also, it seems to be hardware non-dependent, showing up on several different models of system.
Hopefully I've given you all information you'll need. Let me know if you have any questions.