What is your op sys? is it W7 64bit? I found the following info on tomshardware.com/forum
"Windows 7 comes with .net framework 3.5 Sp1, .net framework 2.0 also included in this package you can go to: Control Panel-->Programs and features, and left panel you should see an option for "Turn windows features on or off" click there and you can see .net framework installations."
If .net framework option is turned on try uninstalling by turning off the and after uninstall restart your machine and turn it back on. This might help also are you using a thrid party picture viewer and sofware? If you are you might wanna get the latest updates for that software.
Windows 7 will not let you install .net framework 2 you will get a compatibility message.