Hi again,
I posted some months ago a blog covering installation of Cisco VPN-client to Windows 8.1.
With Windows 10 there is a new problem and the solution is covered in here.
http://www.vmwareandme.com/2013/12/solved-windows-8-and-windows-81-cisco.html#.VcHDMW6qpBc
Do first you have to install Citrix Deterministic Network Enhancer and reboot if required. Then you can install Cisco client succesfully.
Bit strange, but atleat it works 🙂