Some of the last security updates did break some themes so my answer is you did the right thing to fix it.
As there will be no more W7 updates, you can leave it as you set it and keep up with full backups in case of a hard crash or full blown other issue.
Since the final Windows 7 update (a few days ago), my Windows background reverted to a default, and I cannot reapply my chosen image. Also I could not mute the Windows sounds.
The only way I have found to fix the problem is to Restore an old version of Windows 7 (and selected "do not allow automatic updates").

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