So after roughly a 2 month break from the Witcher I decided I wanted to do a Death March play through. However when I go to launch the game through GoG it does nothing. The only thing that changes is how long ago I played the game in the library. It changes to just seconds ago or something. I tried launching it with Task Manager opened on another screen and it didn't even pop up on that. Any help would be appreciated.

Did you change something on your PC (like upgrading to Windows 10)? --> If yes: install Visual C++ Redistributable for Visual Studio 2012 Update 4 64 bit version.
Can you start the game without Galaxy (Am I right that you mean GOG Galaxy with GOG?)?
Have you tried updating Galaxy and Witcher 3?
Have you tried to repair the game (more button)?

I did upgrade to WIndows 10 so that might have caused it. Once I'm able to I'll see if my PC has any outstanding updates for the system and for Visual C++. However after my upgrade to WIndows 10 I was prompted to update/re-download Visual C++ Redistributable for some other game that required it so I'm not sure thats the problem I have.
I did mean GOG Galaxy and I cannot for the life of me find the executable for The Witcher anywhere.
Both The WItcher and Galaxy are as up-to-date as they can be and the first thing I tried was to repair it.
Thanks for the reply though I will do some more digging to see if I can get anywhere.

Right so I tried all the options you stated above. It didn't work so I though I would just re-install it. No problem I have it on disk so i don't have to worry about downloading it. Well I installed it successfully. However now in Galaxy it says that the game is awaiting release. >.>.

The problem here is that Witcher 3 is a 64bit game and need the 64 bit version of C++ Redistributable for Visual Studio 2012 Update 4. Most software till now is still only 32 bit and need only the 32 bit version of C++ Redistributable for Visual Studio 2012 Update 4. After you install the game again from DVD you get the right version.
If you have such a problem again for other games/software google for it and download it from Microsoft website. There is a activation patch you need before you can play the game.

From Witcher 3 FAQ:

Q.: I installed the game and it is well after 19th May, Galaxy still displays 'Waiting for release' and the 'Play' button is greyed out. What can I do?

A.:
1. Exit Galaxy
2. Open it up again
3. Select the game, click More -> Manage -> Verify/Repair
4. Wait for the patching process to finish
5. Play

https://www.gog.com/forum/the_witcher_3_wild_hunt/faq

i have the same problem cant launch the game screen shot of the error

Are you using a mod (Console Enabler mod)? Update it.
If not remove or rename the dsound.dll and start the game.
https://www.reddit.com/r/witcher/comments/3dqyrt/107_game_doesnt_launch_matchescounterror

thanks removing the dsound.dll worked

I have just bought the game. Seemed to run fine yesterday but now, after installing updates, the Plat button is grayed out and I can't start the game.