You will google this to no avail and be angry that you did. After creating a batch file and using the RUNAS command in command prompt and after seriously considering dropping $100 for PowerShow, I HAVE FINALLY FIGURED IT OUT! And luckily, the solution is all in powerpoint, no programming or money involved.
This is how to run two different powerpoint slideshows on two different monitors at the same time (without either pausing!)
Open your first slideshow.
Click the Slide Show tab on the ribbon > Click Set Up Slideshow > Click Present by Speaker (Full Screen)
Open your second slideshow. Drag it to the other window. Set that window in the Slide Show tab to “Show On” that monitor.
Click the Slide Show tab on the ribbon > Click Set Up Slideshow > Click Present by an Individual (Windows)
Now present both slideshows. They will work and show at the same time! We have one slideshow that has videos and the other is just a regular slideshow with no sound.