Ok so I've created a practice game.And after champion selection,when the loading screen started ,the icons of the champions were all blue with no names the font was very little.I thought it's because i put new files in heroepak.rar ,for the vivi skin,but when i put back my backup file ,I still had this problem.
Edit: OK it seems that when i put back the backup file i forgot to remove ".backupfile" that i added rofl everything is fine.

Unfortunately, editing the internal files for League of Legends can create problems with the patching process. Before anything else, you should try completely reinstalling the game from scratch. Be sure to uninstall and delete any remaining folders before trying to install the game again.

http://signup.leagueoflegends.com/download