That's it!
I installed everything without problems, all drivers form all devices (including even Microsoft mouse & keyboard and Samsung monitor which aren't really needed) yet i still have this message in Windows 7 x64.
The only "outside" devices are the USB audio card RME Fireface UC, which is installed perfectly and the Nvidia GTX 760 video card which is also perfectly installed.
I de-activated the integrated graphics (set in "enable if PCIe not present" in BIOS) and also the Audio device which i don't need as i use the RME USB device. Also Consumer Infrared is de-activated by BIOS.
Basically i have no more physical devices to install, yet i see this message in the Windows device's administrator under "Other Devices--> Unknown Device"
Must be something from the motherboard that has not been installed with the provided drivers.
I downloaded and installed all the lastests versions of each Motherboard driver and BIOS, so i don' know what it could be...
Any thoughts?