I lately tried to uninstall the Microsoft .net Framework 2.0 from my system only to find out that I could not do it. The uninstallation program told me that other applications installed on my computer were depending on that Microsoft .net Framework 2.0 and Microsoft was displaying the link http://go.microsoft.com/fwlink/?LinkID=91126 to a Microsoft support page for uninstalling Microsoft .net Framework 3.0.
While that did not help I looked through my installed programs to find out which applications could depend on the Framework and the only other programs that I could come up with were the other Microsoft .net Frameworks that were installed on my system. Both the Microsoft .net Framework 3 and 3.5 were also installed on the computer.
I decided to uninstall the other two Frameworks and the only that I could uninstall was the last one, the Framework 3.5. Once that was uninstalled I was able to uninstall the Framework 3.0 and finally, after that I was able to remove the Microsoft .net Framework 2.0.
It seems that the newer Microsoft .net Frameworks depend on older versions that are also installed on the computer. The only viable choice you have if you want to uninstall an older version is to uninstall the newer versions as well and install them again after the old one has been uninstalled.