Windows ME to Windows 2000

Have a Compaq Presario laptop that was upgraded from ME to 2000……..Now can not get the NIC or modem to work correctly…..Have installed the latest drivers from Compaq site, still a no go. System senses that there is a connection on the NIC but will not communicate. Have uninstalled and reinstalled drivers for both modem and nic, TCP/IP……Any ideas?