b) fail you can wipe and rebuild your PC without any look (and remember the golden rule of backups ... test them, they're not backups unless you can get the data back).
Agreed. I forgot to mention earlier the old adage that an untested backup is not a backup (and yes, even I have fallen foul of that rule, and it cost me a healthy five digit sum at the time.... although in my defense it was a rather complex and unusual sequence of events and IBM were partially to blame for their role in matters !).
The whole point of backups is that due to a virus / hardware failure / just because you feel like it, you can at a whim format your drive and know you'll be able to re-install the software from its original sources and then re-instate all your important files.
If you can't do it at a whim, then you're not backing up properly.