Assassin's Creed 4 stuck at 15%

[vpdmec]

Hey, please help.
I was playing ac4 for 2 week or so. But I got stuck at 15%, after assassin land mission, restart the game, stuck at same. My cousin had played it, but he had no problems.
My computer specs are as follows
Intel core i3 3rd gen 3.3ghz 3220
4gb ram
1024x768 screen
My cousin has the same. Can anyone help?
Pls....

 

[vpdmec]

Even my computer supports ac3 with full graphics enabled, but I play ac4 with lowest graphics. I use game booster 3 too.

 

[Abqu]

My PC knowledge is limited, but have you tried uninstalling the game, updating drivers, and trying again?

 

[vpdmec]

My PC knowledge is limited, but have you tried uninstalling the game, updating drivers, and trying again?

Yeah, twice. My computer is new, so I didn't get much updates.
But ac3 works with high performance.