My normal strategy for handling failed domain controllers is to re-built it from scratch. This is a simple and safe strategy - restores are complex. Virtual environments (and imaging) increases at the risk of having a domain controller restored in an unsupported fashion. The 875495 hotfix is required by Microsoft, if you want support of your virtualized domain controller. If you have plans for virtual DCs, you must read the whitepaper, it also contains other important issues - e.g. remember that your virtual disk must be just as safe as a physical one.