Advanced Uninstaller Pro by Innovative Solutions has what they call an "installation monitor". If this function is enabled prior to installing a new program, it supposedly takes a before and after "snapshot" of the registry. The theory being if you eventually remove that program it will know which registry entries to also remove.
Advanced Uninstaller PRO: A Swiss Army Knife for PC Users - Completely uninstall any program, even if it has no uninstaller of its own
The questions I have is how long before the registry has other changes made to it that were not included in that "snapshot"? What happens to the other registry changes if that "snapshot" is used? Will other programs, apps, even the computer itself suffer problems because an outdated registry backup is reinstalled? I asked these questions of Innovative Solutions and never got a response.
To me, the "snapshot" feature is too much like a registry cleaner. Many of the people on this Forum (including MSMVPs and others who have been using Windows 7 when it was still in Beta and before) strongly recommend that registry cleaners are not needed. Windows 7 is quite capable of handling the registry on its own. So I would be very careful about using any 3rd party product that claims to restore the registry to a pre-existing condition. The only exception I'd make is the Windows 7 System Restore feature. Create a restore point before installing any new programs and registry information is included. Or better yet, create a system image which is a "snapshot" of the entire hard drive, not just the registry.
Just my 2 cents worth.
I'm using that Advanced Uninstaller Pro and it does a fairly good job. It has the "leftover scanner" that runs after running an uninstaller and searches for anything the program may left behind.
I've used the "installation monitor" you talk about a couple of times, but it does not work as you say. It's not a snapshot what it saves, it's the changes made to files and registry. It keeps a log sort of "that file has been added, that registry key modified fro X to Y value, that another key added", etc. When unistalling using that log, it simply reverts those changes recorded and nothing else. It's not a complete restore of an old state, it's a trace back of some concrete changes. Of course, things changed after the install survives that method.
And about the "registry cleaners are not needed", it's completely untrue. That phrase of "Win7 is capable of cleaning itself" is nothing more than a marketing lie in order to convince people to buy, but nothing technically really. Programs may leave things on registry and Windows will NEVER go and delete those on its own, those accumulate there until explicitly deleted by an uninstaller.......... or a registry cleaner.