It's hard to admit this, but I have had a great deal of trouble with Windows 7 and VPN - connecting to a remote VPN service from a Win7 Desktop.
I looked everywhere to try to resolve it, when I finally ran across this little gem:
netsh winsock reset catalog [resets winsock] netsh int ip reset reset.log hit [resets the TCP/IP stack]
Run these two at the command line, REBOOT, and (at least for me) all of my issues with VPN connection failures were GONE !