Use Process Monitor (it'll start capturing when opened). Then, try to start Opera so you get the error. Then, you can stop capturing (File -> uncheck "capture events").
Then, look for an access denied event in Process Monitor to see what file has permission issues. It's probably one or more files having to do with the Microsoft Visual C++ Runtime. It could be "C:\Windows\System32\mfc140u.dll" for example.
Then, the idea is to Reinstall the Visual C++ Runtime versions and if that doesn't work, right-click on the problem file, goto "properties -> security -> advanced", add your Windows user account (or user group) to the file and set it to have full control.
But, like @p-h-f said, you might want to use the system file checker to see what else is messed up on your Windows too. I'd also use CrystalDiskInfo to see if your drive is still good.