I'm trying to re-install software on windows xp but it doesn't install because of previous entries in the registry. I therefore require a registry cleaner tool (preferably free) that will 'clean up' the registry and remove all the left-over crap from previously unistalled software that shouldn't be there.
I had encountered some similar issues like this on the net and some of these are resolved by using third party tools
Try to download a latest tools of team Paretologic called pc health advisor
it is safe and free for cleaning the Windows registry and defragging.
I'm sure this is the tools you need.