Although .NET Framework versions can be installed in any order, Aaron Stebner
who works for Microsoft, answers questions at the MSDN forums and writes about .NET Framework issues on his Blog, recommends to install .NET Framework in reverse order
from the most current to the oldest. He advises this because the most current version includes the the latest updates of files shared by all versions so that helps to eliminate some bugs and installation issues. A couple years ago, Aaron wrote Should I re-install the versions of the .NET Framework in a specific order?
Thus, when installing .NET Framework, the software should be installed in the following order:
1. .NET Framework 4.5 <- Windows XP users can skip as this version does not support that operating system
2. .NET Framework 4
3. .NET Framework 3.5 SP1 <- installs .NET Framework 2.0 SP2 and 3.0 SP2 so you do not have to install them separately
4. .NET Framework 1.1
According to Aaron, most programs do not require .NET Framework 1.0. If you need .NET Framework 1.0, it will have to be installed before installing .NET Framework 4 because the .NET Framework 4 setup blocks future installation attempts for .NET Framework 1.0.
Therefore, if you need .NET Framework 1.0, the software should be installed in this order:
1. .NET Framework 3.5 SP1
2. .NET Framework 1.1
3. .NET Framework 1.0
4. .NET Framework 4
5. .NET Framework 4.5 <- Windows XP users can skip as this version does not support that operating system
All .NET Framework versions are available for download separately from Microsoft's download center
so you can bypass Windows Update. If a version is not listed, simply type the version name in the the Search box at the top.