I have two computers, computer a and b. computer a has 2 network adapters and splits cable internet throught to pc b. PC b was recently formatted I installed win xp pro and installed all the updates, it works fine. PC a has been running for a while with everything installed and I decided to install all win xp's updates including service pack 1. But straight after installing service pack 1 on pc a, it can't use the internet, pc B can still use the internet but Pc a can't. All newtork protocols etc. are in place and it should be working fine. As soon as I un-install service pack it starts working again, but upon re-installing it stops working. Could it be because I installed the service pack with norton still active? Thanks.

How To prepare for an SP1 installation (from M$) 1. If you use Faster User Switching, make sure that all other users are logged off from the computer and that only you are logged on to the computer; you must be logged on as an administrator. 2. In the event that the installation fails, you need to ensure that you get the most out of data recovery. On computers running Windows XP Professional, to maximize data retrieval, create an Automated System Recovery (ASR) before you begin installation. For detailed instructions, see "To create an Automated System Recovery set using Backup" or "To recover from a system failure using Automated System Recovery" in Windows XP Help and Support Center. 3. Perform a full backup of the files that you keep on your computer. 4. Stop any real-time virus checkers before you install SP1 because they might interfere with your installation. (Be sure to restart the virus checkers after you install SP1.) Check the space requirements for installing SP1 on your computer. See article Q326583, "Hard Disk Space Requirements for Windows XP Service Pack 1," in the Microsoft Knowledge Base. Important Automated System Recovery (ASR) will not restore your data files. For more information, see "Backing up files and folders," "Restoring files and folders," and "To create an Automated System Recovery set using Backup" in the Windows XP Help and Support Center. Caution Before you begin the installation, remember to perform a complete back up of all your files on your computer and close all open programs.

Andrew: try the install again with Norton Auto-Protect disabled. if still no joy, try this fix after the install: http://www.cexx.org/lspfix.htm