mobile

Hi! I have a new galaxy core 2 duos (about 1 month old). I decided to root the device using kinguser to cheat some games (its my first time to root a smartphone). I installed game killer and gamecih. The gemekiller said "root privilage needed" and the gamecih said something like "error root". I did some research and it seem to be that i need to use supersu. So i did installed supersu and updated it. The first update was successful. But after supersu granted gamekiller and gamecih, still the "root privilage needed" and "error root" appears. Now, without uninstalling supersu I installed superuser thinking that it might solve it. Supersu detected that there are two superuser and said something about uninstalling, so I tapped the uninstall key. Since I cant get gamekiller and gamecih to run, I decided to hard reset the device. After hard reset I reinstalled supersu and the problem occured "installation failed!" when updating it. I have tried a lot of solution from the internet and still no luck. I have tried installing using zip, using su bb, hard reset, full unroot kinguser, uninstall, reinstall, etc.

But I think I have a clue. When installing using zip, this message appears: "E:ERROR tmp/sideload/package.zip (status 255).

Please help, thanks!