My iPhone is stuck in recovery mode

This is my problem and how I solved it. The problem started that my iphone 4s began to restart every 2-5 mins. I read about this and the suggesion was to install an new update or restore an older version of firmware. The only problem is that when connecting the phone to computer, it keeps connecting and disconnecting and I can hear the 'ding' sound of connecting/disconnecting of USB!

Another suggestion was to RESET ALL SETTING form phone. I did that and in the middle of the process the phone restarted and kept restarting and got stuck there. Again, I read about this and the suggestion was to use the recovery mode either to upgrade or restore the older version of firmware.

When I entered the Recovery mode, I couldn't update or restore the phone. I read about this and some suggested to use softwares like tinnyumbrella to force exit from the recovery mode. I used a program called Reiboot to force exiting the recovery mode but the phone was stuck on the apple logo and switched off after a while. Many threads were pointing out that this is a hardware problem and the device should be taken to service and in some cases replaced.

My last try was to reset the hardware. This can be done by openning-up the device and disconnect the battery and the power cables going to the electroic components. You can follow this video which is made specificly for iPhone 4s and stop at 3:09 (https://www.youtube.com/watch?v=jPqkuxkrbdY) .

Then I connected all disconnected cables back to their place. Afterwards, I tried again to restore the iPhone using iTunes and it worked perfectly. Neverthelss, I lost all the data on the phone.