Ever wondered how to determine which version of the framework is installed on a machine? I did today when I had to do some debugging on a component I've written earlier; I needed to know the version of the framework and more specifically whether service pack 1 for framework 1.1 was installed.
To check for the service pack you need to do the following:
The .NET Framework version 1.1
With the .NET Framework 1.1, a new registry hive has been created specifically to make it easier to find the service pack level. Start Registry Editor, and then locate the following registry key:
Key Name: HKEY_LOCAL_MACHINE\Software\Microsoft\NET Framework Setup\NDP\v1.1.4322
Data type: REG_DWORD
The data in the SP value tells you which service pack is installed for the .NET Framework 1.1. For example, if the value of SP is 0, no service pack is installed for the .NET Framework 1.1. If the value is 1, Service Pack 1 for the .NET Framework 1.1 is installed.
Note that this method cannot be used to detect if any hotfixes are installed for the .NET Framework 1.1.
If you want to know more about determining the framework version itself you can check out 318836 How to obtain the latest .NET Framework service pack.