Boot into BIOS setup, if this is a new Win8 PC look for a setting to disable Secure Boot. Then enable Legacy BIOS or Compatibility Support Module (CSM). This should remove any EFI Boot Disk from BIOS Boot order. Set DVD drive first to boot, HDD second. Then set SATA controller to AHCI. Save changes and Exit.
Then boot into installer DVD or flash stick burned or written using tool and latest ISO for your licensed OS version here.
At first installer screen Press Shift + F10 to open a Command Box, type:
SEL DIS 0 (after confirming Windows 7 target HD #)
CREATE PARTITION PRIMARY SIZE=102400 (for 100gb partition, adjust as desired)
FORMAT FS=NTFS LABEL=”WINDOWS 7″
Next click Install Now to Clean Install Windows 7 to the partition you created.
In addition read over these steps to understand the tools and methods which work best to get and maintain a perfect Clean Reinstall – Factory OEM Windows 7. The steps are the same for retail.
The purpose of creating the partition above is to wipe the HD and define an Active partition which resolves most install failures. Afterwards you can adjust the OS partition size in Disk Mgmt, create other partitions as desired.