Try this
All you have to do is download the 2 files from these links:
1.Link in VM
2.Link in VM
and install them on your PC. Then turn on the USB Debugging option in your phone and connect it to the PC. Make sure that no other phone is connected to your computer. Then run Root Genius on your pc, it will automatically identify your phone. Then just follow the on screen instructions. Click on Restore Data on the phone if prompted during the rooting process. After 100% rooting procedure is complete, you'll find KingUser app in your app drawer. Then reboot your phone (not necessary but recommended). Your phone is now rooted. Enjoy.
The process usually takes about 10-15 minutes & restarts your phone multiple number of times , so there's no need to panic.
Unroot
There's an option to unroot it in the KingUser app. On a safer side you can always take titanium backup of all the data and format the phone before handing it to the service center coz they will format it anyways.