grayman

I have a modem that is hooked up to my computer via USB port, I'm trying to hook up a wireless router which requires me to use ethernet cables running from modem to router to computer. When I use ethernet cables it tells me I have no access or conectivity to the internet, but as soon as I disconnect everthing and re hook up my cables from the modem to the computer using the USB port, I instantly have internet. What do I need to do to make the ethernet cables and port work so I can hook up my wireless router. I'm slow when it comes to computers so use really simple words and directions when explaining how to fix this problem. I'm also scared of screwing things up so if I need a computer guru to do the work let me know.
Cheers