SteamOS
SteamOS
You're looking to run SteamOS on an HP laptop with an A8 APU. It's a great idea for experimentation, but compatibility can be tricky. Some hardware may not support it, so checking the official SteamOS documentation or forums is a good next step. As for keeping your Windows 8 installation, you can usually preserve it by using a bootable USB drive and restoring from that, rather than just leaving the key on the laptop.
If you're looking for something simple, just follow the instructions. Keep in mind that steamOS is designed for vendors who sell PC-style consoles to offer a controller-friendly interface for streaming on TVs. Valve doesn’t block you from leaving Steam and going to the desktop, but it’s minimalized—so you’ll need to install extra packages to match a full desktop experience. You might find better results with Linux distros built for desktops like Solidity or Ubuntu. Steam should run on those platforms, and all the Steam games will function properly.