HKEY_USERS\S-1-5-21-1482476501-1788223648-725345543-1003\Software\Microsoft\Windows\CurrentVersion\Applets\SysTray

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Applets\SysTray

Those were the only two keys I found.

Have you tried just using system restore? Do you have a registry backup that you could restore?