This is my first post so I apologize ahead of time for leaving out pertinent information....

I have a Demension L Series Desktop and I just purchased the following router:

LINKSYS
EtherFast Cable/DSL Router with 4-Port Switch
Enterprise Networking, Broadband, Cable/DSL Ethernet, 4-Port 10/100 Switch , One WAN IP Address required, Protocols: TCP/IP, UDP/IP

Manufacturer Part# BEFSR41
Dell Part# 008611

I have a cable modem and only purchased the router to serve as a firewall, as DELL suggested (I have Norton internet security but it takes up too many resources).

Now my question, I do not know anything about connecting the router and I need to know if I need an ethernet card or something else to connect with.

I am really lost on the subject...Any help would be great! Let me know if you need further information about my sysytem....