DLNA is a murky topic at best. A month ago I purchases a large screen Panasonic ST50 series plasma as the main tv for family room. It is a so-called "smart" tv, that can access the Internet, also other devices through DLNA such as media servers. I also have several tvs scattered throughout the house as many people do. Some are newer "smart" tvs, others the older "dumb" variety.
I have many music files, videos, extensive photo collection, several TB's worth. These are located on a single Windows PC and also were on several external drives that can be plugged into the pc and accessed that way, a pain because it's hard to keep track what is where. Over the years I've burned many DVD's so I can play both my music and videos on a tv via a DVD. These days, kind of a crude method, but hey, it works.
Here's what I'm in the process of doing to get up to speed:
1. I purchased a WiFi router. Your Internet access plugs into it, and the router connects to your main PC both via Ethernet.
2. Any "client" can join a home network either being hard wired via ethernet or wirelessly if your router supports that.
3. Purchased a NAS (
Network Access Server) which is a box with a mini computer and 1 or more hard drives.
4. In process of copying all my multimedia files to the NAS, advantage, can be accessed when PC is off, NAS stays on.
5. Smart clients like my new tv can "see" my files via my WiFi network by using DLNA and play them on the tv.
6. For the "dumber", older tvs, I use WD Live tv, a hardware based media server.
You're probably interested in #6. This is a relative cheap device sub $100. There's other brands that do more or less the same thing. It gives access to your files on a network, also to pay services such as Netflex, several RSS feeds, other things. It as a device is wireless and connects to your network that way. These days so do a Play Station, many DVD players, etc..
The WD Live has a HDMI out. If your tv doesn't have HDMI I'm not sure since I didn't need one, there's probably converter cables to match your tv inputs. You would need such a "box" for each device you want to give access to your files. You don't need multiple PC's. If you go this route you don't really need another media server, that is built into the box. I got MC mainly because of all the cool things you can do with it, especially in file handling.
So far I have seven wireless devices on my "home network", tvs, tablets, cell phones and of course tvs. The minimum you need is some kind of router to wirelessly broadcast your files to other wireless devices in your home, and one or more media servers, either hardware or software based. The NAS is optional and only practical if you have tons of files, you can easily access the files off any networked PC and you don't need multiple pc's. Obviously to work anytime, such a PC would need to be turned on.
The reason for having a hardware media server such as the WD Live is it bridges the gap so your dumber devices can join a wireless netowork. It itself is wireless, but it's output are hard wired so you don't need cables running all over the house, just a short run of one wire from the WD live to the dumber tv or whatever. Yes, there's other ways, this seems to be the most simple and cheapest.