Slooow download??
Basically, registry repair software works to fix windows registry by scanning various areas of your computer's registry to see if there are any invalid registry entries. When data changes on your computer - for example you delete a file and the registry doesn't remove the invalid data and often times you will continue to have a reference to a non-existent file remaining in your registry. Because of this reference to a file that is supposed to have been deleted, the registry continues to get filled with invalid data.