A desktop with ethernet and a laptop with ethernet and/or wi-fi.
I cannot access internet on Windows 7 on both, but with Ubuntu 13.04 I can.
I already rebooted and reseted the modem/router, a D-link DSL2640B, but without solution.
It happend some time after install a HP wireless printer using Windows, but I think it's not related.
I can ping to 188.8.131.52 and sometimes appears a yellow triangle on ethernet connection icon.