I have found a solution for the HID Sensor Collection driver problem.
It seems that the driver is using something from the Windows Media Framework and because it can't find it on my Spectre X2 it fails.
This Driver issue will happen on all HP Spectre X2 that have installed Windows 8.1 Pro N (N stands for European version) because it doesn't have Media Feature Pack installed by default.
In order to fix the HID Sensor Collection driver problem I have installed the Media Feature Pack for N and KN versions of Windows 8.1 from here:
http://www.microsoft.com/en-us/download/details.aspx?id=40744
After the instalation the sensors just start working.
This is a BIG ISSUE and HP must do something to address this!!!
Big thanks to Wiab from Lenovo Comunity forum for sharing the solution with us:
Regards,
Mircea