This is exactly what he is looking for - a tool that will allow him to capture changes made to a system when an application gets installed. I don't understand why everyone is looking at system imaging tools. I understand he has asked for imaging tools to create his snapshots and then another tool to compare them but that is way too complicated and of little value. What happens if he wants app #1 and app #3 but not app #2 on his system?

How about looking at application virtualization technologies like Altiris's Software Virtualization Solution (SVS)? SVS allows you to capture the install of an application and see the files and registry changes it makes when installing an application. You can then save the application and all of its files and reg entries as a single file. Going further it also captures any changes made while running an application, which is also something you need to consider as some apps make further changes after running the first time. SVS is for enterprises though you can also download and use a personal version with all the same capabilities and features of the enterprise version. I use it for most applications on my home system and it is especially good for trying out new applications since you can simply delete the captured application after your done with it as easily as you delete a file! Once you have all your applications captured this way rebuilding a system is as easy as installing the OS or an image and reimporting the captured application files. Very quick and very easy! Check it out! http://juice.altiris.com/node/86