MS .Net Framework 2.0, 3.0, 3.5, etc, do I really need all/ any of them?

My laptops HD is running low and looking at the 'add/ remove programs' utility, I noticed I have a lot of .Net Framework updates. I thought a new update should replace the old but they are listed as follows:

MS .Net Framework 1.1 (No filesize listed)
MS .Net Framework 1.1 Hotfix (KB928366) (No filesize listed)
MS .Net Framework 2.0 Service Pack 2 Size: 185 MB Used: Rarely
MS .Net Framework 3.0 Service Pack 2 Size: 179 MB Used: Rarely
MS .Net Framework 3.5 SP1 Size: 28.57 MB Used: Rarely

I assume 1.1 has been replaced as there is no size listed but do I need 2.0, 3.0 and 3.5?

Is .Net Framework even neccessary on a XP laptop used mainly for the internet, MS Office, multimedia (streaming video, Mp3 etc)?

Sorry if this has been covered elsewhere, cheers

Don't worry about them just leave them there. Make sure you check for Microsoft Updates regularly. The .NET framework is needed for some programs to run correctly

Thanks, I'll make space some other way