I was using windows7 for some reason I wanted to install windows 8 .I had two drives (c and other one is shrinked from c ie (f when I was installing windows 8 I was not allowing me to install it was displaying error that windows cant load on GPT form of drive so went to cmd prompt by clicking shift+f10 then diskpart , list, clean when I cleaned it deleted both c and f drive and all data was lost and only one unallocated drive was created please help to recover my data