I am getting the following message when trying to boot from a Windows 7 DVD on a PC: "BOOTMGR image is corrupt the system can not boot".
The PC is currently running Windows 8.1 x64, and I tested the drive with another DVD (non-windows), and it opened the contents properly. Any fix/further troubleshooting for this issue, as I need to urgently format the current Windows partition and install a 7 (since the 8.1 on it is not legit, and PC has OEM for 7 Pro)...
You omitted the make and model of this PC. But the error looks to be common when the BIOS is set to secure boot. I can't be specific as there is no PC detail so go find out how to change the BIOS to CSM or Legacy (look, this is not a standard and why make, model is required.)
Now you may be able to boot your W7 DVD and then fail as the HDD needs to be erased. Do not format that HDD, just remove all partitions. For that I use GPARTED.