If you uninstall the Unkown device in device manager and then use the drivers from the manufacturers website does that make any difference? You should reboot after uninstalling in device manager and then Plug and Play should pick up the device in need of drivers when you get back into Windows.
Are you sure the unknown device is in fact this Ralink item (unplugging it will confirm that as it won't come back after a reboot).
I cant even install a driver for it as it says the it it already up to date... I uninstall the 'Unknown Device Driver" that is supposedly installed, unplug it from the header and reboot. I then install the correct software, plug in the adapter's cord into the spare USB header and it still comes up as an unknown device.
Here is the device info
here are the instructions from intel:
The link in the instrucions is dead.
Have you confirmed this unknown device is, in fact the correct bit, by unplugging the RT8070 and rebooting to see if that unknown device goes away? If the same unknown device is still there then that means its something else without (the correct) drivers.
If it won't let you use the latest drivers from the manufacturers website (that I linked to above) by the standard install (and you'll have to read their instructions for more on that), how about updating to these drivers by extracting their contents to a new folder and updating the driver with the new ones (using the update driver button in the driver tab of the device properties)? I don't have one of these devices but this is what I'd normally do in the event of problems installing drivers.
Have you edited the registry on this PC at all and how has the PC been performing generally? Which USB port are you attempting to connect it to - try a USB 2.0 port and NOT USB 3.0 or simply change to a different USB 2.0 port to see if that makes a difference.