touchscreen - Tablet Touch Screen partially unresponsive

I have an Android Tablet with Android 4.1.1, some days ago, the screen started to have random touches around the top of the screen, and sometimes, the top of the screen was unresponsive.
After a factory reset, the problem wasn't solved, but now the top of the screen had stopped being sensitive... I opened the tablet and cleaned the screen.
Now it stopped the random touches (Sometimes they happen again), but the screen still doesn't respond, what do I do?