Sorry for the delay. I hope this is still useful to you.
I asked for the model of your MB as a check as some do not, or only partially support EFI mode.
Using Diskpart from a W7 installation CD to clean a used SSD/HDD. Wipes the drive of Data makes it Unallocated Space. For safety, I advise disconnecting all other SSD/HDD except for the OS installation one to prevent accidentally wiping the wrong drive.
Place the CD in the Optical drive and restart the computer.
At the first input screen. Choose your language. > your region. > accept the keyboard input.
Please follow the instructions on the images below.