Uninstalling Windows Updates and security patches

Each one patches a security, stability, or performance issue, so yes, each one is necessary. They don't load like individual programs, instead modifying existing code and processes in most cases. Whether that has a positive or negative effect cannot be immediately determined, but aside from additions such as Windows Firewall it should not have any noticeable effect. If so, that in itself would be an issue.

As to a rollup, it adds new functionality and support to the operating system while a service pack is a conglomeration of previously released and internal patches. Such may or may not remove the need for previous updates to be applied individually, but doesn't remove the patches themselves. For instance, if you install SP2 you may only see the lone SP2 entry in add/remove programs, but the dozens of patches included in it are still being applied 'behind the scenes.' Thus, there really is no getting around it unless you choose to leave the holes open.

John

When a security patch is applied, it replaces a file that had some buggy logic code in it with a fixed version. It's not something that gets applied every time you boot. That would be horribly inefficient and rather ineffective too. There would always be a window of opportunity for exploiting any known security hole if that were the case. It would make the patching process pointless and futile.

And while they aren't needed in the strictest sense of the word, they are very highly recommended to be left installed. If you start removing them, you may very soon find yourself reminiscing fondly about the days when the biggest problem you had was a 4 minute boot time.