xp boxes cannot connect to anything outside of the network

Our xp boxes cannot pull anything from outside of the network until reboot
or renew address. I can get to anyhting inside of the netowrk including our
internal webserver. Butanything outside of the router, XP will send but not
recieve. IE times out.(page cannot be displayed). ...
It will still resolve addresses..eg..ping google.com
[216.239.37.99]
So i dont belive it is a DNS problem
When i check Event viewer i see thefollowing:

IPSec Services: IPSec Services failed to get the complete list of
networkinterfaces on the machine. This can be a potential security hazard to
the machine since some of the network interfaces may not get the protection
as
desired by the applied IPSec filters. Please run IPSec monitor snap-in to
further diagnose the problem.

If i release and renew my ip, or reboot, everything is fine. This is only
effecting the XP machines, not the 2000 or 98 machines.

any help on this would be appreciated....