Touchscreen isn't responding.

[Tam Ado]

I was using my S5 and suddenly nothing I touch registers. I've started and restarted and it doesn't still respond. What can I do?

 

[B. Diddy]

Welcome to Android Central! Are you able to boot into Safe Mode? https://support.t-mobile.com/docs/DOC-28456. If it happens in Safe Mode, then the digitizer might have failed, which would require a trip to the repair shop.