Can I downgrade Windows 8.1 to Windows 7

[JacobRocks12]

I have Windows 8.1 and a Windows 7 Home Premium 64 bit ISO, will it mess it up like will aero still work? I tried VirtualBox with it but had to choose 32 bit (it was the only option) and aero didn't work!
Can I just put it on a CD or USB and install it like that, my dad did the ISO to his laptop and it messed it up so bad the most all drivers were not install with it. I found the official ISO but I haven't tried it at all on VirtualBox or reseting a PC. I rather just downgrade my PC than reset because I can't reset it because I accidentally formatted the Recovery Drive. So can I downgrade?!?!?!

[camerongray]

The ISO isn't what matters, you need a valid licence for Windows 7.  If you have Windows 8 Pro then that gives you downgrade rights to Windows 7 Pro however if you are running regular Windows 8 you will need to purchase a full Windows 7 licence.