How to Stream Video from a Mobile Device or Computer to a TV

My ChromeCast Does NOT Have the Cast Screen option in the Chromecast App. Just Updated to Make Sure. What Gives? Samsung Galaxy s4 att
 
I've got an Asus laptop that runs Windows 8.1, but doesn't appear to support Miracast transmitting.

Is there a USB Miracast transmitter I can get? I've already got a Roku 3 to catch and that works from my android phone and tablet.
 
1) Can any of this be considered tethering? And can a mobile provider penalize you? I actually dropped AT&T a few years ago over a tethering issue and they actually told me that even stream video to your TV is considered tethering.

2) Can this be considered illegal or violating some form of copyright law?

Correct me if I am wrong, but I believe none of these methods will let you stream NFL from your mobile device to the big screen on Verizon.
 
And being that the NFL along with Verizon has this kind of DRM mechanism in place (Chromecast indicated as such when I tried this), I would suspect it would not be long before other content providers start using this kind of "stick" mechanism to milk more money from consumers.
 
Does tethering your device (phone/laptop/kindle) to a smart tv via Wi-Fi use up data? I'm on a very limited internet data plan unfortunately.
 
I have a HP Notebook running Windows 8.1 and a new Samsung TV with Screen Mirroring. When I add wireless device to my laptop it recognized the TV but won't connect. When I click Project and pick the TV my TV screen and my Laptop screen both go black for a couple of seconds and the TV says loading. Then it stops and goes back to regular TV. I am learning that the two may not be compatible. Is there any kinds of work around for this that doesn't have me using one of my HDMI ports as there is only 2 which are currently in use.
 
What if PC don't support miracast or other screencast, or there is no screen cast on android mobile device? is there software for this purpose or usb transmitter is needed for this purpose?
 
Thanks for the valuable info! From this list, I use ArkMC for iPhone and ArkMS for my Mac. Apps work good, they are user-friendly and wirelessly stream my media to different compatible devices. That's much cheaper to buy a lifetime app, rather than spend more money on cables and adapters.