dear expert kaisay hay app... may nay apnay laptop hp i3 probook may window karni hay us may already 8.1 chal rahi hay but courrpet ho gae hay... may nay bootable usb banai hay window 7 ki iso lay k 4gb ki usb par jab wo complete ho gae to laptop k sath attach kar di restart kar k window karnay laga to yeh error ata hay and window 8.1 fir c start ho jati hay any key press karnay par.

error yeh aataa hay
operator system not found