PC specific vpn issues

Hello,
I have 10 computers that CAN connect to my SBS 2003 pptp VPN.
I have 1 user who cannot. He is running XP sp2. He gets 721 error.
I can run pptpclnt / pptpsrv successfully from this client to the
server, so GRE is
not the issue.

(Dell server / 2 NICs; 1 NIC connected to local network; 1 NIC
connected to public network.
I have rerun CEICW, reinstalled RAS on the server.


I have msconfiged and booted very clean on his PC (no AV, firewall,
defender, etc)


I tried connecting to another company's SBS vpn on his PC and have
same issue.


I can connect to vpn with his account on another computer.


It fails with any account I try on his computer.




So, it has to be computer specific.


The fact the pptpclnt / pptpsrv succeeded really has me stumped.
Any ideas? Are there any alternative vpn clients that run under xp
and connect to a sbs 2003 vpn?
thanks