Win 8 is tied into BIOS, but how deeply?

I needed a new laptop so I bought an Asus 750 with Win8. I figured I could put Win7 on it if I got too frustrated. It turns out adding an SSD and fresh Win7 install is not easy.
Windows 8 is somehow tied into the BIOS according to the Asus forums, but no one could explain how or what to change to allow other hard drives and OS. Some have "gotten lucky" with their Win7 installs.
The Win8 forums said this is to combat piracy, only Win8 can be run on the laptop which is checked with the BIOS. A new install is possible on EXACTLY the same hard drive if one fails. Changing hard drive type or OS is not allowed.
All comments appreciated.

 

To install Win 7 my understanding is that you go into BIOS, disable Secure Boot, and select Legacy rather than UEFI. That enables you to boot to your Win 7 installation disk, reformat to NTFS and install 7.

 

Thanks for the insight.
Asus has different names but same smell.
Disable Secure Boot is the same and the hint when you turn it off tells you the dependency you need to toggle to get a CD to boot and install.

 

Now I am wondering how much Microsoft has opened the doors to BIOS malware. More interaction between the OS and the BIOS might be cause for concern.

 

Second installment.
Upgrading the OS to 8.1 Pro did not upgrade the key in the BIOS. If I have to reinstall I will have to enter my key again. So much for that feature if you upgrade.
Some Dell users have said their BIOS was updated. My Asus was not.

Do we need a Win8 sticky with upgrade info and how the embedded keys work?