mac/pc router issue

Hi. Just got a new macbook and trying to connect it to the wireless router where I live. It worked the first time I tried, but once I’d closed out of Safari that first time it won’t connect again- says it has no connectivity even when I’m sitting right next to the router. Everyone else in the house has pc and I don’t know if that would affect anything, but I tend to doubt it since it worked once. Anyone have thoughts on what I should try?