Issues tyring to stream media to smart TV

I have a new Samsung smart TV, and when connected either wired or wireless using Allshare (samsungs sharing software on PC), a message appears on screen about re-connection every 15 mins, whether just watching TV, or worse when playing media from PC and disrupting it. I have NO problem with the TV accessing BBC iPlayer or YouTube.

So it looks like something on my PC is disrupting the connection, can anyone suggest what it may be?

My PC setup: Win7, belkin router & Trend av&firewall (thru which I have made exception for allshare).
Power settings ok, and PC & HDD set to not go to sleep.

 

Go to the Device Manager in the Control Panel. Find your connection. Right click it, click properties. Make sure the computer can't turn it off to save energy.