Drivers don't stop working unless there was updates and something broke for it.
Check device manager> Human interface Devices. Look for something with touchscreen. Probably would be listed like HID Compliant touch screen.
If it is there it sees it. If not and there isn't any unknown devices then you might have had hardware that failed on you.
Also make sure you don't have it disabled. There can be a button on the keyboard with your F1-F12 keys that disable it as well.