Question : Cannot connect to the internet

I have four computers connected to wireless D-Link hub. Two are connected by ethernet cable, two wireless. One of the computers suddenly stopped being able to connect to the internet. I am not sure what I did, because this computer was my daughter's and I was cleaning it up for use as a travel laptop. It says the wireless connection is strong, but I cannot connect. However, if I put an IP address in, I can connect immediately. I know it has something to do with the DNS, but I don't know how to fix it. I have reset the modem, and the router a couple of times. The link light is blinking on the Time Warner cable modem, but I am able to connect using the other computers so it probably isn't that. What could be wrong here?

Answer : Cannot connect to the internet

Tried using System Restore? (go back to a time when the problem wasn't there)
Start - All Programs - Accessories - System Tools - System Restore
or Start - Run - c:\windows\system32\restore\rstrui.exe