I have 2 computers in the house and 1 wifi router, but only 1 computer can connect well. What can I do?

I have 2 computers in my home that can both connect to my wireless router. However, one is able to connect easily and stay connected while the other has more trouble. It gets very little connection and is constantly dropping it. I know it isn't the distance or anything because even the 1st computer can still access my internet from my neighbor's place.

The 1st one that can easily connect runs Windows 7, while the other runs Windows 8. Not sure if that matters but you never know. I'm not sure if the router is possibly to blame, or if the Windows 8 PC has problems with its wifi connections, or something else entirely. If anyone has any input or advice, it'd be very helpful. Thanks!