I tried to install Windows 7 in dell vostro 15. I turned off secure boot, booted into windows 7 installation menu, then I opened command prompt, went diskpart,and cleaned the whole HDD, but it showed "A Required CD-DVD Drive Device Driver is Missing" after that I rebooted the laptop and everything is as it was. but I did clean the drive, it showed successful. but every file is present there.
please help, I did not understand this behaviour.