Visual Studio 2010 Professional - repair installation, will it lose updates?

Question

This is a specific example of a general question that often puzzles me on Windows.

I am having problems with Visual Studio 2010, so I need to try to repair it.

There are two items in the Programs list: Microsoft Visual Studio 2010 Professional, and Microsoft Visual Studio 2010 Service Pack 1. Service Pack 1 leads me to a simple menu to remove or re-apply SP1. The other entry, MSVS 2010 Pro, leads me to the usual pretty installer that offers to add to, remove or repair my installation.

First question: it says some of my prerequisites are not correct any more. Would it say this if they are newer than when it was installed, say because of SP1 or other Windows updates?

Second question: if I repair, will it repair files to the SP1 versions, or the pre-SP1 version? Would I have to re-apply SP1 after repairing?

Third question: as part of the repair process, it re-installed .NET 4. There have been updates to this via Windows update. Will they be lost now?

As well as these specific questions, I wonder if there any general principles I can apply to adding/removing/repairing software in Windows to know how it will behave and the correct way to achieve what I want.

Answer 1

In my experience, Repairing VS 2010 will reinstall all RTM dlls. So all your updates are lost. After repairing VS 2010, you will need to re-apply SP1.

And regarding security updates, VS 2010 installer does not un-install the updates. So you will have entries in Programs and Features for the updates, but the actual dlls may have been replaced with older ones.