cCleaner is one of many registry cleaning program. I don't know if it's the best one, but it's free and it hasn't caused me any trouble which is a good thing. It's one of three FREE tools from Piriform, a UK company gives away their software, relying on donations for support.
You can download a copy from www.cCleaner.com. It's a little over 2MB, so should only take a few minutes to download on a dial-up line.
You probably DON'T want to use the default settings, it may clean out more than you want. Check back in a couple of weeks and I'll make recommendations.
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