Did you run the installer "As Administrator" to avoid UAC issues? In some cases A/V applications prevent from a successful installation. In case your system is a domain member, you may also check domain policies.
If all the VMware services (e.g. VMware DHCP, NAT, ..) are installed and running, try and see whether running "Restore Default" from the Virtual Network Editor (make sure you start it "As Administrator"!!!) can fix the issue.