Microsoft advice

If there is a problem with your system

reinstall

But not in Linux, come on guys, and gals, we can do better than that.  Say you don’t have the time to figure it out, say there is a point of no return with some changes (there is never such point, even in Debian, it just takes careful steps to retract from sid to wheezy), say it is not worth it, or say that you are clueless of what could have gone wrong.