Install windows 764 bit over windows 864 bit

are you looking to dual boot or run windows 7 ?

dual booting requires its own partition, if you install over windows 8 windows 7 will overwrite it

You can do a clean install of windows but you should not be doing a roll back or downgrade of OS as it will fail.

First check whether your PC supports Windows 7 (check the manufacturer's homepage whether drivers are available).

If that is the case make sure you have made recovery media of your system so you can restore it to factory defaults if needed.

Then change the secure boot option in the BIOS. It would have to be disabled so you can boot your installation DVD and install the new OS. There should be an option in the system settings of Windows 8 to turn the secure boot option of the BIOS off.

Another option would be to use Hyper-V which is included with Windows 8 and then install Windows 7 as a VM inside that.

No issue as long as you install the OS as new install (formatting the HDD) and not an upgrade.

It's required by the company to work with their existing software. It's not my fualt they are not up to speed with updating their software... just needing to comply with them

Obviously you need to do the downgrade then.    So (a) gather the appropriate drives;  (b) turn off Secure Boot in the UEFI setup;  and (c) boot to your install disk and install '7 as usual.

thanks! I learned something new!