cannot connect to internet anymore

We have an XP computer that no longer can connect to the internet. Last week it connected fine. The pc is on a LAN with a DSL modem to ISP. Other pc’s in building connect ok. Remote location, so I am trying to fix without going out in the snow.

User’s network properties show the LAN connected but few packets are being Sent and 0 received. Also I had her do an ipconfig, and the IP address has been changed.

Had a similar problem with Win98 pc,in that it could no longer network. This was due to users kid unloading KaZaa or something like that, that blew out network. I had to reload os completely to get it going. Want to avoid that this time if possible.

Any thoughts??