@fadingstar If you follow the steps exactly how I explained, then MBR to GPT conversion procedure will be automatic.
Done. Thank You everyone for your immense help. A special thanks to @Tito . Thank you for being patient with me. Really appreciate your help.
Like you said conversion can be done without erasing data, can you give me any reference to that post, blog or guide because it's very lengthy and annoying process to transfer all your data to another hard drive and again transfer into your PC? So next time if I ever again in the same situation I don't have to copy/transfer my files to other drive.