How to downgrade Raring Ringtail back to Ubuntu 12.04?

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http://askubuntu.com – I've just updated my Ubuntu 12.04 up to Raring Ringtail Daily Build, and now I wanna get back my Precise. I found out that I can't use ATI legacy drivers because of version of kernel and X-Server version. If there is any way to install this driver with Raring, please post me. If there is any way to downgrade kernel, lol, let me know. I just wanna play Team Fortress 2 on my PC with integrated video card, without using noisy HD6850. Integrated one is Radeon HD4250. Thanks. (HowTos)