Windows 7 UEFI/EFI mode BIOS

In simple terms there is legacy mode which is windows xp, vista or 7 and various Linux… these use the old master boot record (MBR) file system. The free windows 7 boot tool can make these.

Modern systems are windows 8 and above which use the (gpt) system which has several advantages with large files and multi-stream transfers but windows 7 won’t be able to make use of most of it.

Windows 7 is compatible (that is, it will install & boot up) with both systems and if you have a blank hdd then use what ever one you like but they are not interchangeable so if you already have a gpt partition then that locks out making a mbr on that drive and vise versa.

To make a gpt compatible boot you need a modern tool and I personally recommend Rufus (http://rufus.akeo.ie/) but there are others.