|See if this very handy, safe to use and often suggested here, utility will help resolve it the problem.|
Do NOT use the big "obvious" download button at the top (right) of the screen. There are four download links/mirrors a little further down. Use one of those.
Let it run the whole gamut of test/fixes. It will offer to do most of them, including backing up the registry - which do let it.
Ideally (I seem to recall) t suggest safe-mode if possible. I have run it in normal mode and it did resolve a few problems for which I couldn't find solutions. Perhaps follow the sae-mode path if viable?