Windows 7 wont boot from usb

[xNexeon]

I have built a new gaming rig last week and tried to install Windows 7 of my USB Stick, it showed me an error saying something like "Please select proper boot media and reboot" or something along those lines.

I have checked if the boot order was set to boot from usb, and even tried opening boot menu and booting from USB

I then ran a live USB of Mint Linux, which worked like a charm and downloaded Windows 8.1 onto the same USB, it booted no problem and installed with ease.

I stuck with Windows 8.1 for a while and i don't really like it and really want windows 7

My motherboard is the MSI z97 PC Mate

I've installed the lastest bios update

Any help will be appreciated!

 

[Tom Tancredi]

I have built a new gaming rig last week and tried to install Windows 7 of my USB Stick, it showed me an error saying something like "Please select proper boot media and reboot" or something along those lines.
... downloaded Windows 8.1 onto the same USB, ...

Where did you download Windows from?

Why not upgrade it to W10 (which is still free to do) which is like Windows 7 (the GUI) as compared to W8?

FYI W7 & W8 are no longer supported for the consumer, so any issues you have with it will illicit the same response from Microsoft anyway, to instead use the supported W10 OS.