How to keep the Xorg settings from the Live CD/USB?

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http://askubuntu.com – For some reason no matter what I do in regards to getting proper ATI Drivers, nothing works. However, testing out the OS in a Live USB is actually perfect. Full-screen flash works, 3D graphics work, and everything is snappy. Is there a way I can install Ubuntu without the "default" graphics drivers changing? Like I said, everything is fine and dandy until I actually install the OS and reboot. Then I'm greeted to a glitchy, useless mess, which prompts me to switch to a slower, laggier Proprietary driver. I have an ATI Radeon HD 6850 graphics card, and I'm on Ubuntu 12.04 (x64) (HowTos)