So, I'm installing Windows 7 on my custom built rig, and, when it asks where I want to install Windows 7, I select my Hard Drive(The other option is the installation disc). When I select, it says Windows cannot be installed to this disc, and says that the Hard Drive has an MBR partition record. Then it says I need install to a GPT disc. How do I format this? I have an Asus M5A97 Le R2 Motherboard iwth UEFI BIOS if that helps. Thank you.