I have to agree with the anti-registry cleaning comments. It's best to just avoid registry cleaners.
If you're experiencing issues with speed during start-up, try reducing the number of things that load at start-up. For instance, instant messenger programs like Windows Live Messenger (MSN), Yahoo Messenger, and AIM by default load automatically at start-up, but if you go into their options, there's an option to stop this from happening. Then you can just open these programs as you need them instead of having them all load at start-up.
You might consider going into "Uninstall or change a program" and removing programs you don't use, especially ones that come on at start-up. If you are unsure what a program is or whether or not you need it, search for it online or come on back and ask us.