Hello, My computer knowledge is limited, so please advise!
I try connecting to my roommate's wireless connection, and my PC shows the wirless network with a stong signal. I select it to connect, and after a moment its says "Unable to connect to Network", doesn't ask for the password or anything. The router was previously setup prior to my arrival and is able to connect to my roommate's Mac no problem.
I am not a computer guru, so I need all the help I can get! Please help!
You need to check the settings in the router -- specifically the wireless mode should probably be set to mixed mode and that the Wireless Access list is disabled. Access list is a way of filtering users in or out by the unique MAC ID assigned to their equipment by the manufacturer.
The most common issue is wireless security so I would check the security type matches your computer's and , obviously, the password.
To do the above:
Connect the computer to the router with an ethernet cable.
See the literature which came with your router for how to access the user setup screens in the router.