manging

I just bought new Acer notebook and install WInXP Pro SP2.after configure my network setting to be used in my office LAN , i can surf with no problem but after updating windows via windows update,i cannot surfing.i've tried both firefox & ie.My internet connection was fine (for both wired & wireless.I'm connected tru office network) coz both my messenger(yahoo&msn) just work fine..anybody got any idea whats wrong here??? Title Edited - Please follow the forum rules from now on -- Martin L