Cannot continue installation

Hi,

Since a time ago with Windows 7, I couldn't update Flash Player (for both Chrome and Firefox) because of an error message saying "cannot continue because another flash player install or uninstall instance is active". With the update of Win 7 to Win 10 I believed that it would get fixed. But the error keep appearing. I could successfully update flash player to version 18 with standalone installers, but again, with the update to 19 I have the same error message. With such apps like Task Manager and Process Explorer I could never find any instance of any installer running, so, I guess that it could be a Register entry that is not deleted. Or perhaps it's another thing.

I was looking for in this forum and others but couldn' find a suitable answer.

I hope you can help me (and forgive my english).

Thank you in advance.