The quickest and easiest fix if you have it enabled would be to do a system restore to the first restore point before the install of either driver
update. If that isn't available then you can try doing a driver rollback in Device Manager,
right click on the device ans select Properties, click on the Diver tab, then click on "Roll Back Driver".
Another way is to have a look at the Update history in Windows Update, locate both and then see if they are shown in Programs and Features and uninstall them from there. You don't say whether you are running 32 bit or 64 bit, but if you still want to update the video driver go to the appropriate link, Drivers & Support | GAME.AMD.COM Drivers & Support | GAME.AMD.COM
and get the Catalyst 10.4 driver package.
P.S. Once everything is back to original or updated, the next time Windows Update offers a driver update (especially a video driver update) don't install it, instead right click and select "Hide update".