Root with Kingo root; stuck at turn on screen This morning I root my phone with Kingo Root. This night my phone suddenly turned off and restarted while I was browsing with Chrome. Then it permanently stuck at one of the turn on screen.

I tried factory reset by - Home + Power + Volume Up but my phone has no response. But restart by Home + Power + Volume Down works.

I am using a Samsung A7. Does anyone experience this before? Anyone providing other suggestions?

Thanks,
Simon
Based on the information you provided, your phone is Soft bricked.
You can make the phone working by flashing a stock rom to the phone(unrooting).
The process of unrooting is a thing that you should do very very carefully. Once your phone is hard bricked, in no way, you can get back your phone.
Since you didn't explain the scenario completely, I found a procedure to do an Unroot.
This website http://trendblog.net/fix-soft-bricked-android-device-first-aid-guide/ (listed first in google search), describe in detail the process and you can do what they said based on your situation.
They are providing solutions for soft-bricked devices in different scenario like if stock rom is available in memory, if not etc. etc.
The full procedure is so long and do it carefully
Don't forget to take a look at : XDA Developers