Pc and Mac can't see eachother

Hello,

For some reason, when I open Finder on my MacBook Pro, I don't see any of the computer anymore that are in my network. I have a network with a few other windows PC's in it and this MBP and I remember I always saw other PC's showing up automatically in the left sidebar of my Finder. For some reason, they're all gone. They are supposed to show up automatically there right? Or at least I can't remember having to add them manually.

Also, on my Windows PC, I can't see my MBP anymore. Neither am I able to print anymore from my MBP to a printer connected to a Windows PC and shared on the network. Any suggestions why this is and how to solve it?

The reason I came up with this is that I'm trying to set up streaming. I have a Mede8er connected to my network on which I can see my Windows PC, but not my Mac.

Weird huh?

Hope you can help! Any more info needed please let me know.

Cheers,