i'm having a problem in WinXP.

We are using ProxyServer2.0 on WinNT4.0 SP6 PDC Server on our Network Domain. And the scenario is this:

Using Win98SE on client computers, the Domain\Users can access www, pop3 & smtp. but when i upgraded the clients into WinXP Pro, the Domain\Users cannot access www but still can access pop3 & smtp.

Note: No changes from user's rights before and after upgrading from Win98SE to WinXP Pro.

what dya think???