Can I override the bios at startup so that it will recognize a new hard drive - for linux?

There should be no need to play around with your bios settings. Linux will install on a brand new hard drive as the sole operating system, or on an existing hard drive alongside Windows without any problem.

If you haven't already got a Linux distro, have a look at
http://www.ubuntu.com/download/desktop

Download whichever version of Ubuntu you prefer (LTS- the long term support version is recommended).

When the .iso file containing the operating system had downloaded, burn it onto a dvd, or install it on a usb drive.

Insert the dvd into the drive and restart or switch off/switch on the computer. The dvd will then kick in and offer you the choice of trying Ubuntu without installing, or a full install.

If you're using a new, empty hard drive just follow the on screen instructions and Ubuntu will install as the sole operating system.

If you already have Windows on your hard drive Ubuntu will give you the choice of either erasing Windows or installing Ubuntu alongside Windows. It's your choice.

Installing Ubuntu alongside Windows creates a dual boot hard drive. At start up you just choose which OS to use - Windows or Ubuntu. If creating this dual-boot system Ubuntu puts a (Linux) boot loader into the Windows OS so that Linux is recognised.

If you save the Ubuntu file to a usb drive you then have to change the bios settings so that your computer uses USB as the first boot device. Then restart your computer so that it boots in from your usb .. and Ubuntu will begin installing.

Whichever you use - dvd or usb - during the installation process Ubuntu will ask you how many GB of hard drive space it should use? You do not need to physically partition the hard drive. Linux will do it for you.

If it's a desktop PC you are using with Windows on the first hard drive and are fitting a second hard drive to install Linux on, or have installed Linux on the second hard drive .. and find that Linux doesn't appear at start up, it's because there's no Linux boot loader in Windows.

I quit using Windows many years ago.