touch screen doesnt working.

i accidentally uninstall my phone's go launcher app knowing my phone has its own launcher. isnt it? but when i press the main menu button it all went black. why is that? i turned it off. when i open it again. the only thing i see is its black screen, lock screen, date and time. but then i cant unlock it. it cant be touch, plus the back light didnt went off. it is always on. pkease please help me.