Controller drivers won't install on Windows 7

I want to play Guitar Hero III Legends of Rock on PC, with the guitar controller for Xbox 360 via USB. But when I plug the guitar into my computer, Windows 7 searches for drivers and does not find them on Windows Update. So my guitar won't work in game.
I searched Google for Guitar Hero III X-plorer drivers, so I could download them and install them manually, but I didn't find anything. Instead I saw many forums where people had the same problem as me and were complaining that drivers weren't available in any way. I tried every answer I saw but nothing worked (that included manipulating stuff in the device manager, installing this, and even rebooting the computer, reinstall the game and other BS). My computer won't recognize my guitar.
I think Microsoft just deleted these drivers from Windows Update, at least for Windows 7, because a friend with Windows 8 instantly installs the right driver when he plugs the guitar in, and everything works perfectly fine (we tested this with the same guitar and the same game).
I heard about JoyToKey, which is supposed to "convert" controller button presses to keystrokes on a keyboard, but it doesn't work as my controller isn't recognized and doesn't appear in the device list.

Does anyone have ideas ? :(