AzisTroyanov :
Unless you bought it through Steam then I guess you're outta luck and your going to have to stay with uPlay.
Why does your computer freeze? Do you have conflicting programs? Do you have viruses?
I presume it is viruses but services like Microsoft Security Essentials do not pick anything up. It freezes basically anytime after it boots. I might want to add that this is a new build and I am reusing a laptop hard drive.