Hey guys first of all I searched a lot on this site but didnt get any exact answer to my questions. Dont know something happened automatically and all the folders permissions changed automatically and there came a lock icon on all of my folders and files. Then I searched on this site and got the solution as this command

sudo chown 777 -R $USER:$USER $HOMEIt solved my problem half way, it removed the lock icon but now all folders permissions are read only so please guide me how to reset all the folder permissions as it was previously?
I'm using ubuntu 12.10
Thanks