Updating to 8.1 Pro; Logo Appears, Boots to Vista

So I recently purchased Windows 8.1 Pro x64 bit for my Second computer. I came home and Made sure the computer worked (Hasn't been used in the past 2 weeks) everything went perfectly fine, I checked through 'SecurAble' it says that my Maximum bit length is 64 bit. I popped the install disk in, turned my computer off, booted it from the disk drive, I see the blue Windows 8 logo and then Vista boots back up. By the way I've went through this process about 3 times, to no avail. I am in need of Windows 8.1 Pro on that computer for guests company etc. Anybody know what is happening?

It is possible that your CD drive is not set as a higher priority than the hard drive in the BIOS boot order?