A. When you get an error in Sysprep, check the %systemroot%\System32\sysprep\Panther folder for the file setuperr.txt. Examine the failure then search for the exact error in the Microsoft Knowledge Base (or I just used Bing).
A common problem I've seen relates to an error executing drmv2clt.dll, which is the digital rights management component. Make sure no Windows Media Player components are running when you run Sysprep. The easiest way is to launch Task Manager, select processes, then enable Show processes from all users. Look for processes starting with wmp and end them. My problem was wmpnetwk.exe, which, once ended, allowed SYSPREP to execute with no problems. I also disabled the Windows Media Player Network Sharing Service to make sure there it didn't start itself again (which it will do if you just stop the process).