All automatic registry cleaners are troublemakers. Every time this question comes up I see nobody that disagrees with that, either. Registry cleaners won't make anything faster, but they are certainly good at breaking things (and the problems don't always appear until later). Automatic driver update software (the "magic" cure-all ones, not those from actual hardware manufacturers like HP or ATI) is just the same.
Check out this thread addressing your very question:
http://forums.techguy.org/all-other-software/840181-solved-regseeker-registry-cleaner.html
If your computer is slow or acting strangely, create another thread about those issues and we'll be glad to fix you up!