Running SysPrep on a Virtual Machine with SQL Server Installed
This is not strictly a virtual machine tip, but a lot of people run SysPrep on virtual machines to create base images that they can redistribute, so I do hear about this a fair bit. Normally if you run SysPrep on a virtual machine which has SQL server installed, and change the computer name in the process, SQL server will stop working (due to the name change).
It is a little known fact is that this can be corrected easily. The details on how to get SQL server back up and running after changing the computer name are available here: https://support.microsoft.com/kb/303774