Originally Posted by MAJED.y
Go to Kies directory in Program Files you will find a directory something like "USB Driver"
inside of it there's USB Driver for Galaxy S II, install it.
maybe this will help someone as well. I had the same problems as you above with these driver not installing. So what i did was the following
installed samsung kies V.126.96.36.19944 with the tel hooked up to the usb and the computer. I did not have USB debugging on in the : settings/applications/usb debug (unchecked)
then I let kies start did not find the drives, so I unhooked the tel. ( galaxy s2) and I enable USB debugging, plugged it in again, started kies and it found all rivers.. NOTE.. it found all drivers but I do not use kies other then to get the drives, I use Odin 1.8.5 which after this , Odin worked just fine.. so you can still upgrade, just without using this Samsung Kies. which sucks anyway