It shouldn't. One of the goals of .NET is that you can version the DLLs.

>Craig,
>
>Thanks for the quick reply. Does installing .NET 4 runtime upset what was already there in any way?
>
>
>>.NET 4 runtime. http://msdn.microsoft.com/en-us/netframework/aa569263 You'll need to figure out which version of it based on what your application does.
>>
>>IIS, and again configured based on your application's needs.
>>
>>Your application
>>
>>SQL Server if you're using it
>>
>>>Hello all,
>>>
>>>I have just converted my web application targeted to the .NET Framework version 4. What do I need to install on the server for the newly targeted application?
>>>
>>>As always, TIA
>>>
>>>Bob