The driver that causes it and is making the installer freeze:
Citrix Xen Windows x64 PV Drivers
Its not visible from Software in configuration screen.
Remove everything from Citrix from your server, reboot and execute the following in cmd with administration rights:
wmic product where name=’Citrix Xen Windows x64 PV Drivers’ call uninstall
Reboot and reinstall the tools again.
gr gr Thomas