I am using the latest version of mirc, and have tried older versions but nothing seems to work. It keeps giving me an "invalid argument" error when trying to connect. This goes for EFnet, DALnet, or any others. I am using comcast broadband but with a usb connection to my computer. Do i need a network card to be able to connect? Thanks for any help.

what do you type?
/server *.*.*

?

Do you have any scripts loaded? Try a clean install of mIRC and see if it can connect.