Just what service packs do I need?

Windows XP

SP2: install it.

That much is easy. It's been out for years, many other software packages expect it, and Microsoft doesn't formally support XP without it.

SP3: so far it's my understanding that SP3 is not actually required. If you just have SP2 you'll still get all the necessary security updates. That being said, I don't expect that situation to last forever, and someday SP3 (or perhaps a successor) will end up being required.

I know that, like you, some folks have had difficulty with SP3 and there's no blanket answer as to what to do about it, as the problems seem to stem from different causes. "Most" people install SP3 without a problem but if you're not most people that's not much consolation. See my tips for ensuring the smoothest possible install, below.

Windows Vista

SP1: Neither SP1 or SP2 are "required" at this point, with one notable exception which I'll get to in a moment. My position on SP1 right now is that it's very likely to be safe to install. It was finally offered to my Vista laptop several months ago, and the installation went off without a hitch.

In a very odd break from tradition, SP1 is apparently required before you can install SP2. In the past service packs were "cumulative" from the original release of the operating system they were patching and did not rely on any prior service pack having been installed.

SP2: is, as of this writing, a relatively recent release. It's not required, and isn't even being offered to all systems yet via automatic updates.

Since SP1 and SP2 are not required, my assumption (admittedly a dangerous path) is that security issues, especially those deemed "critical" by Microsoft, will be available for your system regardless.

Skipping Service Packs

When you elect to skip a service pack that's not required you're generally missing non-critical fixes and new features only.

That being said, in my opinion it's only a matter of time. By that I mean that eventually you will want, or need, to install the service pack that you skipped. Either its installation will become a pre-requisite for continued updates, or you'll find yourself in need of a fix or feature only included in the service pack in order to use some aspect of your machine or third party software.

Installing Service Packs Safely

As we've seen, service packs can, in fact, occasionally cause more trouble than they fix. As I said earlier, even if "Most" people install a service pack without problem, if you're not most people that's not a lot of consolation.

Here's what I recommend:

• Wait a while after a service pack is released. If that means telling Automatic Updates to not install or stop nagging you, so be it. Pay attention to "the buzz" from mainstream technical press - don't be too alarmed if you see some catastrophes - that can happen with the best of service packs for a variety of reasons. But do pay attention to the number and severity of problems, and how they might relate to your computer and its software or hardware.

• Back up. As I said, even with the best of service packs a change this large is bound to cause someone problems. If that's you, you'll want to be prepared, and that means having a full image backup taken immediately prior to the service pack installation. If all goes well, you'll never need it. If all hell breaks loose, you can revert completely - as if it never happened.

• Tread lightly for a while. Even after a successful install, it's worth not planning any large scale changes or additional installations until you're sure that things are working as expected.

So, what if the worst happens, and your Service Pack install resulted in a disaster? You've reverted to your backup, but now what?

Service pack installs fail primarily for two reasons: problems with specific hardware, and problems with - for lack of a better term - messy systems. I don't mean your mess (documents and the like), I mean operating system mess from prior and perhaps incomplete software installations, leftovers and what I lovingly refer to as "software rot".

Start by doing a little research to see if others with machines or other hardware similar to yours are having problems. Manufacturer's support forums are a great resource for this.

Finally, consider a clean install. That's the "reformat and reinstall everything from scratch" approach. It ensures that your system is in it's cleanest possible state prior to installing the service pack.