Minecraft worked fine for long time but one day when i tried to create a new world i have for 2 minutes the dirt screen creating world and after that i ended up in the void, after waiting for another 3 minutes Minecraft has generated 10 chunks but everytime i break a block or placed one i've got teleported back to the worldspawn. I can join a few already created worlds which works fine, but at other old worlds i have the same problem as by creating a new world. I have already reinstalled minecraft. I have also run on the old worlds the Minecraft Region fixer but i hasn't helped, but whe i open a world in MCEdit i have no problems and no corrupted chunks.
ps. i dont use any mods
please help