I’ve seen this one a few times before. You boot the PC and see a blue screen of death with the error : stop: c0000218 – Cannot load the software hive.
Due to a registry file failure, previously this has usually meant a reinstall of the OS, however today I found the following KB article which fixed the problem:
http://support.microsoft.com/Default.aspx?kbid=307545
Not the quickest or easiest of fixes, however the PC is now back to normal!