Zsoft Uninstaller is a free application that helps you uninstall programs completely. Most of the time, you use Control Panel to uninstall a program, and some leftover files and registry entries are usually left behind. These can be useful if you're planning to re-install the program, as they keep your configuration files or saved games. However, in most cases, they just clutter up your system.
This uninstaller takes an interesting approach to this problem: it takes a snapshot of your system before the installation of a new program and then after the installation. Then, after comparing these snapshots, it can tell you what changed in between. Although this is not a new idea, it is a very rare feature in free programs. However, although the idea is good, Zosft Uninstaller fails to deliver.
First of all, it takes a lot of time to make a copy of your registry. Zsoft Uninstaller has to make two copies and check every system file. I am not sure whether all this time wasted on each program's analysis would not add up to the amount of time spent on reinstalling Windows every six months.
Secondly, you have to stop every other running application, which includes your antivirus and firewall. In fact, I think you should stop every stoppable Windows service as well. And although you could theoretically be able to do the first (but I would not recommend it, for obvious security reasons; even more so if you're installing new software), the second option is simply not feasible. The problem here is that any other application can change the registry or some other files and Zsoft Uninstaller will assume that installing a program did it. When it is time to uninstall, these changes will be undone, and if they were made by some other program, it may just stop working.
Finally, there is no control over the changes Zsoft Uninstaller will make, as you only have access to a somewhat unreadable log, which lists all the changes detected by the program. Truth be told, the program does warn you about the potential harm that it can do.
So at the end of the day, trying to keep your Windows error-free by completely uninstalling a program, you risk completely destroying your system. That's hardly a reasonable thing to do.