Originally Posted by
RudraPratap Singh It seems that the Windows Phone 8.1 overlapped with your earlier windows OS installed at the time of purchase. The hard reset is the best option as already mentioned by one of the member. To reset your phone, switch off the mobile phone and then carryout following steps.
Press and hold the power key until it vibrates then release.
Press and hold the down key volume. If the exclamation mark will be shown on the screen, you can now release the button.
You need to input these key combination:
Volume Up > Volume Down > Power > Volume Down.
Your phone will reset and will boot up automatically. This might take a several minutes.
thank you so much for your post, after countless tries to fix my phone, i finally made it thanks to your explaination!