>Hi Gang!
>
>How do you go about installing dotNET 4.0 client and/or extended?
>
>It should be for 32 and 64 bit machines - Windows XP Service Pack 3 up to Windows 7 ?

Firstly, and obviously, make sure that all projects are targeting 'Any CPU' (Project properties/Build/Platform target)

There are multiple deployment methods available - the right/best one will depend on your user base.
Read this : http://msdn.microsoft.com/en-us/library/ee942965(v=vs.100).aspx

Personally, all other things being equal, I favour the ClickOnce method which can be set up in the 'Publish' page of your main project properties. Nice thing about this is that it allows updates/ bug fixes to be rolled out automatically to clients.