M65 mouse not working with new rig

Hey guys. I just finished my first build last night. After I got windows installed (8.1) I started downloading drivers for everything. When I got to my mouse I installed the driver just fine, but the firmware update wouldn't work part way through. It said re plug and try again. I did that and it didn't work. I tried a different plug and it started to say that this usb device had a failure and was unable to be recognized by windows. The only way I can get my mouse to work at all now is by going into the BIOS and turning off Intel xHCI Mode in the Advanced\USB Configuration. When the mouse is working like this I then can't use any of my dpi options. Does anybody have any idea of how I can fix this?

I should add that when the mouse works, if I try to redo the firmware update it says it cant find the device.

Are you plugged into a USB 2 or USB 3 port?

USB 2, but I've tried both.

I hooked up my old computer and re did the firmware update. This fixed the dpi Issue I was having, but now the mouse only works in the BIOS. When I leave the BIOS and go into windows the mouse doesn't even light up.

Try seeing if you can navigate to the device manager and uninstalling the mouse drivers.  re-insert the mouse again and see what happens.

I'll echo what's been said already, nuke your mouse drivers and try again. Having your mouse work in BIOS but not Windows leads me to believe that it's a driver issue. Maybe try it without any drivers, my M65 works fine with the generic Windows drivers. If that doesn't work, maybe check your USB drivers? Those can be wonky sometimes as well.