safe to remove old versions of key software with "Add or Remove"

Looking in “add or remove programs” in XP there seems to be a large number of old updates that are littering my computer.
Mozilla Firefox (en-GB) 22 MB, Mozilla Firefox (2.003) 24 MB Mozilla Firefox ( 24 MB

Microsoft Net Frameworks 3.0, 2.0, 1.1. and 1.1 hotfix 50-80 MB
Javaruntimes SE 14201, 14205, 14206 100MB each
J2SEruntime updates 1, 2, 4, 6 100MB each

are these still in my system or is “add or remove programs” getting confused?
Can I safely remove the earlier versions or will removing them delete important files for the latest versions? If so should I totally uninstall say Java, then reload the latest version to clear some space?

In theory, yes, you’re supposed to be able to uninstall things without breaking other things, but in practice, it’s risky, however, if you have the wherewithal to install the latest versions of everything you currently use, you should be able to get operational again quite easily if it goes wrong.

As I understand it, each system file has a count of how many applications need it - when another app is installed, the count is incremented, when one is uninstalled, it’s decremented (the installers and uninstallers supposedly know their files, but they don’t know each others’s files, making the headcount thing necessary) - when you’re uninstalling and the count for a given file is exhausted, it will be uninstalled, but the nature of the dialog box you get should tip you off here - it says something like “Windows thinks this file is no longer required, but removing it might fuck things up - your call” - i.e. it doesn’t always work reliably.

So. If you have the install CDs and everything for your current latest versions, you should be in the clear. The stuff that came from Windows Update should be easy enought to get back too, if you have to remove it.

Set a restore point before and if you set out on this adventure.

You can’t depend on a certain response in deleting old updates. Only do it if you have the current full install available, and then you should remove the original along with the updates.

I don’t see an advantage in erasing old versions and their updates, as the replacement files usually write over older files. The ones that don’t usually delete the old application, and only save the preferences for the new program.

According to “add or remove programs”, the unwanted? predates take up over 1/2 GB of disk space that I would like back thank you Sun Java. Now I suppose the question is do they physically exist somewhere, or is “add or remove programs” just thinking that they are, whereas what you are saying and I was suspecting that they actually were overwritten and are virtual entries only.

OK digging around in my programmes folder, I find what I presume are all the Java folders, and indeed all the updates are still there. However rather than 7 x 100 MB each as reported by “add or remove programs”, they are only 25 MB folders which I can live with. All the folders look separate and I suspect I can delete each one without problem.
Another thought struck me though in the case of JAVA. Does each Java programme look for its preferred version of Java (e.g rather than 1.50.2) in case in has troubles running on a later version. In that case I would need all the versions.

You found what I was expecting.

I don’t think that the newest Java running will likely be incompatible with programs made for an older version. I expect an application that used a security flaw would be the exception.

Microsoft Net Framework applications often require older versions to work.