What is this folder: C:\Windows\SoftwareDistribution? When I open it I see a bunch of files such as: AuthCabs, DataStore, Download, EventCache, PostBootEvenCache, SelfUpdate, WuRedir and RepotingEvents, but what are these for? Can I delete the files in the Download folder?
It is a record of all your updates.
You can delete the folder in software distribution. You can even delete the software distribution completely. This folder will be automatically created when you apply an update to your OS again.
But. If do you delete anyrthng there, you will not be able to uninstall that update and, in some cases, will find you are subsequently unable to uninstall some of the Microosoft programs, should you need to in the future.
It will not interfere with the performance of your compute,r but is only using hard disk space if left - not resources.
Best left alone, as it contains useful material for automated trouble shooting.
Much the same as said previously. It is your decision.
They are mostly "Contracts" which you have agreed to when installing Microsoft software. If you delete them, it is (slightly) possible, that in a future legitimacy check, Microsoft might find your software illegitimate.
As I said. I emphasise. Why is it bothering you? It is only using disk space. We mostly have a lot more than we need!