If you’re a longtime Windows user, you’ve more than likely experienced a crashed registry. If you’re lucky, the built in repair mechanism will fix your system without too much disruption. If not, you may end up reinstalling Windows and all your applications – something that has happened to me.
There are manual workarounds for fixing a corrupted registry, but it’s very difficult to do using Windows itself. It’s easier using another operating system, like Linux, to access and copy the registry files, as explained in this LifeHacker article.