MS help will take you to loads'a'guff with no relevance at all.
Main thing is - keep all your documents on a seperate partition to windows, preferably an external drive you can unplug. then you can reinstall the OS when anything goes wrong, without compromising your own files. Don't be frightened, regardless of what MS say. It's only a bloody machine for gawd's sake.
Plenty of (usually) good advice on the web. But I repeat - don't be frightened, it's only software and you can wipe clean and start again very easily. So long as you keep your data on a seperate partition to the OS
Then just experimenme
nt!