This problem has come up before and I haven't noticed a good work around posted here. The error doesn't seem to appear if using an Original Windows disc but copying onto other media seems to make it raise its head.
Also, it is not just Gigabyte boards that encounter this problem, other manufacturers also have it so I guess it's a Microsoft thing.
A quick Google search using this : "
windows 7 install a CD/DVD device driver is missing" came up with a lot of hits. Most related to Burning issues of downloaded or copied discs but it is also an issue with some USB installs.
If you can get your original disc back, you will most probably find that this error is not encountered when you install from that.
Sorry not to be able to help further but, as I said, I have yet to find a reliable workaround for this problem.