X51 R1 help needed please

I really hope someone can help me please as I'm not getting much help from other sources. I'll start off by explaining the situation that I'm in so that might help people understand what's going on. When I bought my X51 R1 it came with Windows 7 which I consequently upgraded to Windows 8 then 8.1. In the meantime I bought a replacement keyboard (a Gigabyte Aivia Osmium which has a built in USB 2.0 and USB 3.0 port with two USB leads attached to allow the USB 3.0 port to work, so one USB lead is plugged into a USB 2.0 port on the X51 and the other into a USB 3.0 port on the X51) When Windows 10 became available I upgraded to Windows 10 from 8.1 and generally everything worked fine but I was having a few issues with Windows crashing so after backing up all the files that I needed decided to do a clean install of Windows 10 to see if that helped (which it seems to have done) except that when I went to play a game bought through Steam there was no sound at all (Windows sound works fine) I thought it was just a problem with Steam but decided to check a non Steam game and found that had no sound either. I got in contact with Nvidia who asked me to disable the on board sound in the BIOS. When trying to press F2 to access the BIOS, nothing happened which I thought was very strange as the keyboard seems to work with no problems once I'm at the Windows log in screen so I plugged the keyboard that came with the X51 back in and was then able to access the BIOS to disable on board sound and while that keyboard was plugged in I decided to try the games again (just to reiterate Windows sound is ok) and I was surprised to find that the sound in games worked with the old keyboard plugged in, it appears that something didn't get reinstalled properly when I did the clean install of Windows (possibly something to do with USB 3.0 functionality?) so if anyone can give me some advice to help me solve this (Gigabyte have not been at all helpful but Nvidia are still trying to help) then I would really appreciate it, thank you.