hexxit made my computer crash! help!

[technic stap]

it was my first time playing hexxit and all the files were downloading, during this my laucher froze so i tried to x out of it. nothing happened i kept pressing it and still nothing, the only thing i could do was turn of my laptop entirely. i started it back up and it said i did not have genuine windows but i have a real version of windows, and my desktop backround was just black like the first time you use it. i restored my backround and then went on my way. a little bit later the message popped up again about having a non genuine version and the backround turned black again! i am very sad and kinda scared, what should i do? why would a hexxit crash do this?