.NET 4.5 is essentially .NET 4.1 - it's an inplace update for .NET 4.0 that *replaces* .NET 4. You can't have both .NET 4.0 and 4.5 on the same machine - 4.5 overwrites 4.0 and any 4.0 application actually uses 4.5 thereafter.

So you only need to install 4.5...

+++ Rick ---

>>>Hi,
>>>
>>>I need to install MS .NET Framework 4.?? on customer server (Windows Server 2008 SP2). The server has .NET 3.5 installed.
>>>I found a link to download MS .NET Framework 4.5.2 (URL below) but it is not clear if this is update to Version 4.0 or can be installed on top of any version.
>>>http://www.microsoft.com/en-us/download/details.aspx?id=42643
>>
>>Pretty sure that's all you need.
>>
>>>Also, do you know if I will need to reboot the server after installing this .NET 4.??
>>
>>Don't think so....
>
>Thank you. This is good since no need to reboot.