|Here you go: http://wayback.archive.org/web/|
Apparently it's a pretty comprehensive archive of past web pages - useful if the Google cache doesn't have what you're looking for. However not exhaustive though - and if you control the web content you can stop it from archiving your site if you want. (Bit of shame really as otherwise I wouldn't be in the fix i'm in....)
Thanks for the Directory Services restore tip...I still think my big challenge is getting round the C000021A error though....trouble with the Microsoft support advice is that it either assumes you can get to a command prompt (I can't - yikes) or that you can use the Recovery Console from the Windows CD (I don't have one...yikes).
So I'm still trying to get around the bootup loop...is this where a Linux distro might help me?