My friend had Fedora Linux 23, it's broke, how do we start from scratch again?
Just install a new OS.
Pretty much every linux distro has some sort of tool for formatting the hard drive before you install the new OS.
The current OS is not functioning well, is there a way to install using only bios?
just use a live cd or usb
You put your OS on a flash drive or DVD/CD and then you boot to the media using your boot menu in the bios.
Follow this guide: http://www.ubuntu.com/download/desktop/create-a-usb-stick-on-windows
It will show you how to boot into ubuntu from a usb which has a drive formatting tool. Use that and you're done.