System File Error (-1073741819)

Installed Windows 10 this morning, and I was initially very happy with it all. However then I tried to run a few programs, and I keep getting this same error message; System File Error (-1073741819). It happens when I try to Run As Administrator on .Exe files, including CMD.

Skyrim, Gta V, Ableton Live, Fl Studio, and Pro Tools are all toast.

Anyone know what's up? I've been on hold for over an hour on Microsoft's support line. The girl there admitted they are all very very busy.