How do I install SP2 if I get "Access Denied" or some other failure when I try?

Well, I don’t know what’s causing your “Access Denied”. Given the
state I suspect your machine is in, it could be any of many different
things. I did find one possibility, and I’ll point you at that so you
can give it a try.

Should that not work, however, I do have an idea on how to move
forward, and what I would do in your shoes.

The only problem is that I suspect you won’t like it.

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A little bit of research on the web lead me to this post, dated from 2004: “Access is Denied” message when installing Windows XP SP2. The author does ask for a donation, but ultimately if you read on you’ll find everything you need to try his solution for free as well. You can elect to help by donating, or not, after you find out whether it works for you. Essentially, it’s an obscure permissions thing that uses a download from Microsoft and a set of Windows Command Prompt instructions you can copy/paste to try out.

If that solution fails to do the trick, however, things get stickier. (See update below also.)

In your shoes, I would then backup, reformat and reinstall Windows – and everything else – from scratch. And that includes bringing it completely up to date to SP3 as well as all the latest patches before installing anything else.

I can’t speak for to the printer compatibility problems, but it’s very likely that the SP2 and SP3 installs will work on a freshly installed copy of Windows XP.

The problem as I see it is likely one of software rot. Over time random files and settings get “messed up”. Seriously, that’s about as accurate a term as we can use. There’s nothing specific such that we can say “this is what causes it” or “this is exactly what’s wrong”, it’s just a known phenomenon that things get messy over time.

Even though we can’t point to specifics, we can make some guesses, which is what leads me to this conclusion in your case. One thing that can contribute to software rot is installing and uninstalling software. Or even better, aborted or failed installations.

And since SP2 falls into both categories for you right now (initially uninstalled, and subsequently failed), and it has the potential for touching so many things on your system, I’m thinking it might be a major player in this mess.

Or it could be due to any of a number of other causes.

You could spend a lot of time trying to force things to work, and ultimately still not be successful.

Or you could start with a clean slate.

Hence my recommendation.

Here’s the plan:

• Backup everything. What we’re about to do will erase everything on your machine. Everything. So you want to backup everything first so you can restore what you want later. I recommend something like Acronis TrueImage and a high capacity external USB hard drive.

• Get behind a router. This is important because you’ll be installing Windows XP pre-SP2, which has known vulnerabilities. If you connect to the internet directly you run a real risk of getting infected before you complete the installation. The router will protect you.

• Reformat the hard drive. This is actually part of the next step, but I call it out separately because it’s an important step.

• Reinstall Windows. Boot from your installation CD and follow the instructions. One of the first steps will be to select the hard drive to install on, and whether or not to format and erase it first. After having done so, continue to install Windows.

• Install SP2. At this point you have a choice to either use the SP2 CD you received or to download again. While the CD should be good, depending on how much time has passed, I’d still be tempted to just hit Windows Update and let it install the current SP2 as a download, just in case there’ve been updates. Again, in theory the CD should be fine.

• Install SP3 and everything else. Ultimately, this just means visiting Windows Update repeatedly until there are no more updates left to take.

• Install the rest of your software.

• Restore your data from your backup.

Now, there’s a fly in this ointment: installation media.

Many computer manufacturers don’t by default include the installation media for pre-installed software. In my opinion, this is a totally unacceptable practice since if your hard drive were to die and be replaced you’d have nothing to reinstall from.

So what do you do if you’re in this situation?

Contact the computer’s manufacturer and get the media. If they refuse (sadly, fairly likely for an older machine), describe your scenario to them – “reformat and reinstall” are the magic words – and ask them for a solution. It’s possible that they may have alternative options for accomplishing the task. (So called “Recovery disks” are typically not such a solution, as they don’t actually allow you to reinstall Windows – be sure to clarify that.)

And be sure to avoid the problem in the future by insisting on reinstallation (not recovery) media when purchasing a new machine.

The bottom line is that a reformat and reinstall can often resolve a number of issues, and your scenario sounds like a classic case that could benefit from it.

Just remember to backup first.

Update 19-May-2009: commentor Ken B also points this Microsoft Knowledgebase article on the topic: You receive an error message when you try to install Windows XP Service Pack 2 or Windows Server 2003 Service Pack 1: “Access is denied” that you should also check prior to heading down the reformat/reinstall path.