There are lots of programs out there which claim to be able to do all sorts of things with Registry. They tempt you with free downloads then con you to spend money. I very much doubt they could solve your problem, because I suspect you've deleted or amended something incorrectly and all they can do is spot bad entries and attempt to make changes.
Have you tried to load into Safe mode - this can solve quite a few errors. It not guaranteed but it can do no harm.
Otherwise, IMHO, your best bet would be to try to re-install your system over the top, so that you lose nothing but repair everything.