I’m having trouble with my PC's on my home network ever since I installed service pack 2. So to try and make this easier to explain I'll number my machines. I have 3 PC's on my home network. PC1 is my main computer, PC2 is my FTP server, and PC3 is my wife’s computer. Both PC2 and PC3 can access and transfer files to PC1. PC1 won’t access PC2 or PC3 and PC3 wont access PC2. When I try to connect to PC2 with PC1or PC3 it asks for a password for the guest account even though it doesn’t have one (that I know of anyway). When I try and access PC3 from PC1 or PC2 it says it’s not accessible. I disabled the windows firewall on all of them. I run Norton’s Internet security and also System Works on all 3. I added ranges to cover the IP's of all three computers in Norton’s Internet Security on each machine. Here’s my setup. All 3 computers are running XP Pro with SP2. All 3 computers run into a switch as well as my cable modem. In my Nic properties on all 3 machines I’m running "client for MS networks" "File and print sharing" "QOS packet scheduler" "NetBEUI" and "TCP/IP". All 3 computers are under the same workgroup. This setup has worked for many years both for sharing the internet connection and access to each machine. When I installed service pack 2 it all stopped. Hope this isn’t too confusing! 
