Microsoft update question?

I went to the microsoft update page for XP and it shows that I need:

Microsoft .NET Framework 3.0 Service Pack 1

Microsoft .NET Framework 2.0 Service Pack 1

What are these and do I need them?

Microsoft update question?windows vista ultimate

I think you only need them if you're running software that utilizes it. When I installed TurboTax this year, it told me I needed the .NET Framework so I installed it. I haven't updated it since then.