Not sure what is connected to what in your setup chain but you need to ensure at least one component in the chain is network enabled
Your LG TV is wifi enabled but you need to buy wifi adapter, google chromecast can be an easy option here
Amazon.in: Buy Google Chromecast HDMI Streaming Media Player Online at Low Prices in India | Google Reviews & Ratings if you have a wifi setup already
Next check if your Copa media player has a ethernet port, in that case keeping it wired to wifi router or PC can allow it to access networked locations. And if your media player if the playback source of stored files (movies) then media player router is better option and no need to enable wifi / chromecast in tv
Your Pioneer BDP 450 also supports ethernet LAN
Finally your desktop, you may connect all HDDs to this and install media servers like Serviio or Plex to stream media as DLNA servers which can be readily played back by your DLNA clients (BDP, Media Player, TV with chromecast). But the downside is that even if you are not viewing the movie in the desktop but to enable streaming to other devices you have to keep it on all the time, if such scenarios can happen only once a week, desktop is better option, otherwise see below option.
If you do not have budget for a NAS then you may consider products like the one below
Iomega iConnect Wireless Data Station Review & Rating | PCMag.com
For lan connection, ideally all ethernet enabled devices should have automatic / fixed ip setup in router and connected via ethernet LAN cable to router including your desktop or the NAS.