If I may quote a very good tech on this site when he was once asked about registry cleaners (cleaning), he said,
Stay Away...
It is not condoned by any of the Geekstogo Staff to clean the registry, it has very little to no impact on system performance regardless of what registry cleaner's advertising says.
I think you may find two guides in my signature very helpful.
Maintaining Your Machine, and
Tweak Firefox. <---Look for links in my signature. Also, Adobe Reader can be somewhat of a resource hog, so I recommend uninstalling that and installing
Foxit Reader 3.1.0.0824(exe) <---look for that exact one.
NOTE: When asked to make ask.search (something like that) your default search provider, uncheck the box. Also, make sure to do a custom install, not express or standard, and be on the look out for toolbars and such. Some anti-viruses are known resource hogs as well. Since I'm not Malware Staff, I will just direct you to the
Free Anti-Virus and Anti-Spyware Forum we have here. <---click there. I would stay away from AVG, it seems to have gotten a little heavy on resources as well.
Have you considered upgrading your RAM? This is a great way to find out the kind of RAM (memory) you have and how much of it your motherboard will support. Upgrading your RAM is the most cost-efficient way to increasing your computers speed and performance.
Go to
www.crucial.com. Use their Online System Scanner.
After this, Crucial should have recommended what the maximum amount your computer can handle and the specifications on the kind of RAM you should purchase. Don't know where to buy it?
Newegg is usually the cheapest around and has great customer service.
Hope that helps.