I have been trying to install the net 3.5 or 4.5 framework in my Vista home premium 64 bit for about 2 weeks. I am trying to install a tax program and it requires it. I have been emailing a microsoft tech and it TAKES a week to respond back to me. I have tried all 3 of his suggestions WITHOUT success. The setup just stopps and give a generic 1603 error. Does anyone KNOW where the best support option is for me?Have you followed all the steps here: http://support.microsoft.com/kb/923100 ?yes, I have...Is it necessary to have alll the versions installed?Unless I'm mistaken, .net framework releases are NOT cumulative. I don't know if you can just install the latest version, but if you do it will not contain previous releases. Have you seen this?: http://www.raymond.cc/blog/archives/2009/08/18/easily-install-all-versions-of-net-framework-plus-hotfixes-with-aio-runtimes/ Correct.
They are not cumulative as the Service Packs are...they are seperate entities..NET framework 1.0 is used for Programs compiled with Visual Studio 2002.
.NET framework 1.1 is used for Programs compiled with Visual Studio 2003.
.NET framework 2.0 is used for Programs compiled with Visual Studio 2005.
.NET framework 3.5 is used for Programs compiled with Visual Studio 2008.

No other Version of the .NET framework exists in a final release. Version 4.0 is used with Visual Studio 2010, which is still in Beta.

Therefore: If you are trying to install a ".NET framework 4.5" that you downloaded- don't- it's just a trojan. There is no framework 4.5, and there is no reason to install 4.0, since it will just allow you to RUN programs written in VS 2010 beta, and developers using the beta are not allowed to distribute their applications.

geno368,

I'm really surprised that the install cleanup utility didn't solve your issue. I would suggest uninstalling the net frameworks starting from the newest to the oldest, restarting your pc and finally trying the cleanup utility ONE more time. This has worked for me in the past.

As to your question with needing to install all versions, no you don't. However, installing net 3 or 3.5 automatically installs net 2 because it is dependent on it. So you do not need to install the previous versions, especially net 1 if you don't have any programs that require it.