Why am I invisible to the devices on my network?

Question

I've been using a DLink powerline adapter to establish a wired connection to my upstairs PC. A couple times a day, for sometimes hours at a stretch, I lose the ability to communicate with other devices on the network: my printer, my phone, etc. I'm still able to browse the Internet, though, upload to Dropbox, download files, etc.

The home in which I'm living has a two-router setup. Our ISP provided us with a dual modem/router (an Arris), but the router isn't especially great and we're using our own for WiFi (a Vizio). We're basically just using the Arris as a modem; it's wired to the Vizio, we've disabled its WiFi, it's been set to bridged mode. The Vizio is what I use for the DLink powerline adapter, and it's what every other device on our network connects to.

A few notes:

• When all is well and the devices on our network are visible to my PC, I'm able to 192.168.1.1 into our Vizio with no issues. (Incidentally, when all is well, the network is named within Windows 8 Connections as either "Vizio" or "Ethernet.") When I'm on this weird 'invisible' network, the network is named within Windows 8 Connections as "Network" or "Network 2," no devices are visible when using something like Advanced IP Scanner, and I'm prompted for a password when I attempt to 192.168.1.1 into the Vizio.

• Using Wireshark (which I'm admittedly new to), I can see that packets are being sent to and from where they should be (192.168.1.1). I'm doing no communication with the Arris (192.168.0.1).

• I use a VPN (Private Internet Access), but whether or not it's currently on makes no difference to my visibility.

• There's no pattern to when I'm invisible; suddenly, I'll notice that the network is named 'Vizio' and then all is well.

This has been driving me nuts, and I've been Googling it for weeks to no avail. Any ideas? I'm currently fixated on the fact that I don't seem to be getting a network ID (e.g., "Vizio") when I'm invisible to the network, though I have no idea what this could be symptomatic of.