I have somehow messed up my machine (again) and I would like to go back to an old registry, say from 2 days ago. How do I do that, and is there anything else I need to know?

What's wrong you ask? *sigh* ...it started when I attempted to change my image file associations. That disaster resulted in a box appearing me if I want to download images off my own HD or open them from the location. Then, my wallpaper quit appearing although in properties it says it is displaying, and the final straw was: now every time I click on a graphic file at all it does unmentionable things, the hourglass never stops, the screen goes white, I GIVE UP.

And I promise the next time I reformat I will install Ghost. I have it now based on things I read here but got it after the last reformat.

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1) AMD Athlon K7 1.2Ghz, 320Ram, onboard Audio and Video.
2) AMD K6/2 550Mhz, 194RAM, Monster Fusion, and ? Sound...
3) Linksys router and cable.