So my galaxy S3 have a sort of touchscreen problem, i guess. It has some area on the screen where the touch doesn't work unless i press 3-4 times. I tried a factory reset but the problem still persist. Can someone help me ?
Sounds like the screen is starting to fail. Contact your local carrier store to see if it's still under warranty, and whether they'll give you a replacement. At worst you could contact Samsung directly to see if you can get it repaired.