I seriously don't know how but this did the trick for me.
I was trying everything from uninstalling Drivers and running them in compatibility mode (tried win7 and win8 as well) but nothing seemed to work.´
Then I did as you said, uninstalled, unpacked my Drivers to a Folder, followed all the steps with updating Drivers manually (like in the Pictures) and then a message popped up that the Drivers are already up-to-date and the Installation was done. First I thought it would be another failure but then suddenly the WiFi was on and all the available Connections appeared.
Thanks a lot!
BTW: I am working on an ACER Aspire V3-571G (Qualcomm Atheros Wireless Network Adapter)