I have a RS-232 mouse and my single click acts as double click in win 7!
i also checked all solutions and i tried a new PS/2 mouse but there is the same problem.
i also upgraded my win7 and mother board bios and all drivers. (i have not any problem with win xp and earlier versions of Microsoft os).
i forgot to say my mouse settings are Microsoft default settings and i checked my win with last versions of Avira antivirus but there was not any badware.
I bought it when i had windows 95 and it is my oldest hardware but i don't like to change it because it works in all os include of Fedora Linux,Android,XP but win 7 made a big problem!
it's several weeks i'm trying all solutions but...