ping network problem

I had small network working ok. Had win2000 server and one pc with xp-pro. But when I had to replace server hd and reload win2k I con not get network to function. I kept the same server name and computer name. I also have a SMC router that has dhcp enabled. Im sharing cable modem. I found the PC can ping the server address and name. But from the server I can not ping the PC either address or name.. Please help