Need 2nd Game window

[Catitude]

Gaming Granny on a low frills budget.
I really don't need Sandboxie and I am at a complete loss as to what will work.
I installed Windows 10 which doesn't seem to allow multiple instances of a program up...
I actually have and still play a number of older games that have a Single Player mode as well as a Online, LAN, or multiplayer mode that allows One running instance of the game to be the server & another to join the first as a party, with both of them on the same computer. Usually for purposes of transportation or additional storage & I have been unable to figure out how to do this under the new OS.
The one game I tried Sandboxie with gave me a sound loop, a black game screen & no way to interact. That game plays just fine in windows 10 by itself as a single window game. I tried watching the videos but I can't hear clearly & I really didn't see anything in the FAQ's or tutorials that applied to what I need.

Any assistance would be appreciated. Thank you for your time & patience.

[Craig@Invincea]

What is the game you're trying to run?

[Catitude]

ShadowFlare by Emurasoft

[BUCKAROO]

Outside of Sandboxie, configure ShadowFlare for WINDOWed.

Then copy SFlare.Cfg into its place in respect Sandboxes.

FULLscreen problem worked around. FULL possible with H4X.

Its windowed mode lends itself quite well to multiboxing.

Fullscreen hack involves ForceProcess, AppCompat & Admin.