If the store didn't do what you told them to you should go back anyway whether X2 is working properly or not. That is unnaceptable. If they cannot restore your system to 8.1 with your files intact then they should refund any labor charges... and maybe knock a few bucks off the price of the drive for wasting your time.
Probably some jag off kid maybe barely above minimum wage being "clever". Had a twerp like that ruin the vintage wiring scheme on an old SG right before a tour making my MONTHS of practice with the volume/tone pots mixing fly right out the window. And since it was a cover band... where the guitarist used that exact, old style wiring scheme many nuances became impossible. Little f*cker.
Sorry... got off topic there. lol
X2 was suited for Windows 8. It might be fine on 10 but I would expect some silliness. You also now cannot turn off Windows updates which can be quite intrusive at the best of times... let alone on a DAW.