Hori RAP VX SA Kai wont work with PC

Hi there, im new to this Forum so go easy on me :)

Well, i recently bought an Hori VX SA Kai to use it with my almost new PC
(Windows 7 64x, MSI Z77A-G45). Latest chipset drivers, graphics and so on are installed. Also the latest XBox Accesoires Software.

My xbox360 gamepad works just fine but when i plugin my VX SA the 4 green lights on the X-Button light up for 1 sec and it goes off. Windows tells me no Drivers can be found. In the Device Manager the device is listed as RAP.NX with the yellow exclamation mark.

On my Windows 8 Laptop the Stick works with no problems with the same XBox Controller software.

I already tried uninstalling and reinstalling the XBox Accesoires Software a few times, no change at all. Is it possible that my mainboard (MSI Z77A-G45) is incompatible with this Stick or does the Stick get to less power which i dont think because no other sources are connected to the mainboard except mouse and keyboard and the power supply has over 650 watts. It must be a driver/registry problem...or sth else...
I cant find anything on google with helpful information relating to this specific problem...and there are of course no Drivers around for the RAP.NX Device, only the XBox software, which "should" work...