This worked for me.
1. Install Cisco DNEupdate.
DNE Support - Deterministic Networks
2. Reboot
3. Take ownership and delete ndis.sys (in c:\windows\system32\
drivers).
4. Take ownership and delete ndis.sys.mui (in c:\windows\system32\drivers\en-us).
5. Install Cisco VPN Client 5.0.04.0300 or above.
6. Reboot
7. Windows 7 will repair itself (because we deleted those files). This will take a minute or so and it will automatically reboot.
8. All should work well!