Can I reinstall 10.6.3 with 10.6.3 install disk without erasing the hard drive?

I am currently running Snow Leopard 10.6.8. I am having color profile issues; no matter which color profile I click or calibration change I make, the computer reverts instantly to the default color profile. I can see the changes I make for a split second. I would like to reinstall Snow Leopard 10.6.3 using my 10.6.3 installation disk. Do I simply pop the disk in and click "Install?" Will it rewrite the 10.6.8 data, reverting the computer to 10.6.3? Or do I have to backup the hard drive, erase it, and install 10.6.3? I plan on updating back to 10.6.8, I'm just hoping that reinstalling fixes this color profile problem. On a serious note, I work on CS6 a lot and need to recalibrate my screen for a job I've been offered. On a less serious note, when changing gamma in-game (Amnesia), the slider moves, changing values, but my laptop simply overrides it (in a split second) and applies its own, dark, color profile. If I do click "Install" when I launch the 10.6.3 installation disk, what will happen? Could it possibly end up reinstalling 10.6.3 and erasing my hard drive on its own? I hope not!

If I could get a step-by-step explanation, that would be great, please?

Thank you everyone!