Cable internet not working on laptop

Well, the title basically says it all.

I plug in my LAN cable into the socket on the side of my laptop, but I get the "Limited or no connectivity" notice. I then plug the internet into my desktop computer which is right beside, and it works fine. Right now I'm using wireless, but I'd really like to have my cable internet to work on my laptop ^.^
Also, when I went to my dad's house and plugged in the internet there, it worked fine.

By the way, my computer's an Acer Aspire 5100 downgraded to Windows XP.

 

[wtp]

hmm try these:
Plug in your cable and go to the bottem right side of your screen and click the Local area connection box, properties, internet properties (TCP/IP), properties, if not already clicked click obtain an IP address automatically and do the same for DNS.

go to command prompt ( Start | Run |CMD )
type in "ipconfig /release" then "ipconfig /renew"

if those dont work post a screen shot of what it says when you put type in ipconfig into the command prompt

 

[1337_Byte]

Try restarting the router, if that doesn't work, make sure the laptop can't turn the NIC device off to save power.

 

Sick! I did both of them and now it works! Hehe, thanks so much.