Q: IPhone 4 lock screen touch not working after reboot

Suddenly after a reboot, I found out that I couldn't slide to unlock the phone. I tried to do it so many times but no response. My both buttons are functional and also the magnification feature is also functional, I can zoom in and also swipe and browse the lock screen with three fingers.Cause of the problem I couldn't even answer any incoming calls. So I browsed the internet for solutions and I tried hard resetting my phone by pressing home button and power button simultaneously. Even this didn't work. Please help me find a solution for this.