Which .NET versions to install on XP?

I run several XP computers, and just reinstalled one of them. Now, which .NET versions would I need to install on this computer?

On my developing computer I have these versions of the framework:

Compact 2.0 SP2
Compact 3.5
2.0 SP2
3.0 SP2
3.5 SP1
开发者_运维技巧

Do I need to install all these, or does some include the previous ones?

It depends on what you need to use in your development projects...

You can have just one of them as pst (once) told you or even all together. I am working with .NET 4.0 but I also have to maintain some other projects that use 2.0 and 3.5...