i dont know i usually uninstall the old driver completely, pull pc out of network (otherwise latest driver downloads automatically and in home edition you can turn it off only by making x tweaks ...) and then make full reinstall
ah you mean 770 cant be rolled to older driver because it did not existed. ou boy thats bad.
PS: i bought my 660ftw 3GB for 235Eur in December (including AC3) and i just posted it on sale for 165Eur. Sold in 27 minutes.
Tough i will actually sell it once i got mine gigabyte 770 WF3 4GB so i hope they start to come on sale within week or two. And the guy is also taking my 80+% 500W psu 46->20eur
I guess the copy of my signature did help a little to convince the buyer