most of the registry fix programs i have tried won't give you all the features in the trial. if you have 100 errors in the registry, they'll fix 10 at a time. very frustrating if you're evaluating a product. but there are tons of registry fix programs out there, so i'll assume it's a dog eat dog business.
meeting alert: i've got to goto a meeting. i'll be back after to give you some ideas on where to go to look for programs. sorry for the hurry.
edit: ok, sorry for the interruption. but a vendor bought dinner. can't pass that up.
http://www.download.com/3120-2001_4-0-2-0.html?qt=registry+cleaner&author=&titlename=&desc=&ca=2001&li=49&os=128&swlink=&gfiletype=
i filtered on free, and windows xp, but you might wanna peruse through them to determine how 'free' they are. also, you might wanna consider something that works with vista. that will be my next search.