Hi I fixed this by turning the overlays off for uplay and afterburner/riva display server.
AC III v1.06
Nvidia GTX 660. Windows 7 Professional Service Pack 1 - x64 also have in compatibility mode for windows 7 no SP. and run as admin.
I had the same problem with Call of Duty Black Ops 2. same fix.
I was having the thing where it wouldn't install too.. I switched to another drive and this time, it installed fine.
all this was 3 days of my time.. sheesh.. but I hope any of this helps you guys out there.
peace
Dava
NB: just to say, I feel guilty admitting buying another in this series, seeing how evil (ymmv) AC II was.. I wanted to buy AC I again and it was only available in a pack with AC II ..after FC3 I started thinking I would give Ubi another chance, which I am, with this game. FC3 was amazing.. and fyi not Anti-Catholic. I want a game to explore my faith, not decry it by calling me stupid and corrupt ala~ AC II. I realize there are other opinions..but if you pay for something, you have the right for it not to insult you. .. assassin's creed one is still one the most beautiful games I have ever played, for both faith and journey of location.