What I've done so far.
1. Created a new system restore point. (SONAR X2a 32bit is still on there at this point, and the previous restore point only rolled back as far as uninstalling SONAR X2a 64bit).
2. Used CCleaner to fix the Missing Shared DLLs, Unused File Extensions, ActiveX and Class Issues, and Type Libraries (it seemed to do this by deleting them).
3. Uninstalled Microsoft VC++ Redistributable packages, including ADL(?) updates, for 2005, 2008, 2010, and the 2012 (x86) that was left over from the previous restore point.
4. Ran the Windows Update, but there were none, other than language packages.
5. Downloaded and installed Microsoft VC++ Redistributable 2012 x86 and x64.
6. Now going to check Windows Update again, and then reinstall the SONAR X2a update for 64bit - since X2a for 32bit didn't get uninstalled in the system restore rollback.
7. Will then test the system and software. If the errors and hanging/crashing is still present, I will start from Step 1 and completely uninstall and reinstall/update SONAR.