The registry does not get corrupt. This is not a thing that happens without the system files themselves being corrupted. People blame any old problem on the registry the way they blame any old problem on /etc. Nor, in the case of an actual registry problem, do you have to reinstall Windows from scratch; restoring the registry from backup is the entire point of system restore points, which are created on every update and most program installs. As a bonus, yes, I did upgrade my computer that way. This stuff is pure superstition.