hi i need help please ?

hi. i have an imac. and my grandma has a windows. at this moment i have to use her windows computer cause i dunno how to connect my mac to her internet, i plugged the ethernet wire into my mac & it said it connected but couldnt be used because the IP adress was different. i hate her computer. its really slow & i miss my mac. i know nothing about this stuff so can someone pleaaaaaaase help me connect to my mac ?

Welcome to the forum.

How are you connecting to the internet? Is the modem connected through a router? Are you using the same cable as is used on the Windows desktop? If you are using a router, have you tried rebooting the router? Have you tried connecting directly to the modem? It sounds like it's being assigned a goofy IP address. Any extra details should help...