a. Create a txt file with the name deletepartitions.txt using Notepad, copy and paste the following, Save on a USB thumb drive.
select disk 0
clean all
exit
b.insert the USB thumb drive to the computer you want to reinstall. Boot from WinPE,
c. Go to the drive of USB, if the drive path for the USB drive is E:, just type E: ENTER
d. RUN diskpart deletepartitions.txt
e. Exit
Restart the computer and boot from your Recovery DVD and you should be able to proceed with a fresh recovery or installation.