Network browsing problems

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I have these 2 PC's at work that used to be on a dial-up connection to our network. They recently ran the lines to have them connect directly into the network. Now that they are connected they can see all of the computers in our domain. However, if you try to open a folder on another computer it locks up. I can surf the internet fine, it is just internally that I have a problem. One pc in an XP pro box and the other is a 98 box. If I bring the PC's to a different location they work fine. I had another guy take his laptop down to the trouble spot and he was able to browse just fine on his laptop. This one does not make any sense to me. Hopefully, one of you guys can shed some light on it for me. Thanks