Not only all the updates but non-Microsoft drivers to get it working.
http://www.gigabyte.com/products/product-page.aspx?pid=4739#dl shows no XP drivers so that's not interference but something else altogether.
What do you mean Windows 8.1 "mode"? Most folk write "when I boot Windows 8.1."
Most of what I see today is that today's owners are having to catch up on drivers and app installs. That is, many will install Windows, and hope it all works.
Bob
I built a desktop machine that is dual boot: Windows 8 & Windows XP. Currently it hard-wire connected to the internet from a modem that also eminates WiFi. I have a USB dongle in place for mouse/keyboard wireless communication. I purchased a Frisby computer speaker system that Bluetooth connects to the subwoofer, but the satellite speakers are wired. I purchased a Gigabyte GC-WB867D-I WiFi/Bluetooth PCIe card and installed it intot he machine. In Windows 8.1 mode, the mouse and keyboard function fine and I was successful in pairing the Frisby system. The speaker system was operating via a Bluetooth connection. I am now getting an Error 43 for the generic Bluetooth adapter. Not sure if this is due to interference or some other problem. Also, when I boot up in XP mode, my mouse and keyboard do not function. Does anyone have any possible explanations?

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