AC isn't a great fan of so-called 'registry cleaners'. That makes two of us. They generally do little (if anything) to speed up your PC (or to fix problems) and anything which 'fiddles' with your registry always risks damaging it. The only time you should be trying to 'sort out' your registry is when something is seriously wrong with your PC (in which case a 'repair installation' of Windows is a much better, and far safer, way to go about things).
See here for a relevant comment from AC:
http://www.theanswerbank.co.uk/Technology/Ques tion495877.html
If you need to search AB for anything you simply enter the relevant search terms (which can include the username of a contributor) into the box at the top of this page, ensure that 'Site' is selected and click 'Search'. Theoretically AB's own search facility should take on the task but, to the best of my knowledge, it's still defaulting to using Google until an upgraded version of AB is produced.
However I usually prefer to go straight to Google, which allows you to search any specific website. For example, if I wanted to search the BBC website (and nowhere else) for references to 'rhubarb', I'd use the following Google search string:
rhubarb site:bbc.co.uk
Chris