Lenovo A6000 blank display Unlock button doesn't work

I bought Lenovo A6000 6-7 month ago and it was working fine till now. but now I got a problem with my phone. 

Sometimes while using the mobile, for idle time of 30 seconds the display goes off and when I press Power Button to Unlock the Phone, it doesn't work for 2-3 minutes after that when I press again Power Button to Unlock it works. Sometimes I have to restart the Phone to use. I am facing this issue from past 2 weeks.The mobile is running with Android Kitkat 4.4.4 version Kraft-A6000-S040-150805. Since I have read that there for a lot of bugs in update release by Lenovo Lollipop update so I am not in a mood to upgrade to Lollipop.

I tried by Resetting the Phone but it didn't worked.

If you also facing this problem then Write here you will be get informed if I get Solution. or If you know the Solution kindly post here.

Update : 

The problem has been solved by doing Factory Reset again after removing the Memory Card.

     > Remove your memory card from the Phone.

     > Backup your contacts, apps, messages using Lenovo Mobile Assistant in PC.

     > Copy All Images, Videos and documents of your Mobile in PC.

     > Now Reset your Phone to Factory Setting I hope it will solve the problem. Mine was Solved

Tags: Lenovo A6000 Power button not working

          Lenovo A6000 unable to unlock

          Lenovo A6000 display goes blank for 2-3 min

          Lenovo A6000 Power button is not unlocking the Phone