Nice work, next time please list any side-effects or problems caused when attempting these fixes (no matter how small, people want to know).
Regarding deleting your MSN Messenger application data directory, you should inform the public that they'll pretty much lose most, if not all their MSN Messenger backgrounds, display pictures, emoticons etc..
Regarding editing the registry, if you do delete that entry you'll effectively reset all preferences in MSN Messenger, which is something I don't want to do, thus causing me to get mad at you (note: I didn't really try this, and I'm not mad at you, it's just a scenario. However it WILL reset all preferences)
Regarding Windows Messenger disabling, good job. I'm glad to see you use alternatives like disabling rather than uninstalling which can cause problems and slow your OE/Outlook loadup times. There is an application that is fully compatible with Windows XP Pro and Home, no need for dodgy .vbs scripts or lengthy instructions like digging through the bowels of Windows XP. It's a simple program, get it here
http://www.dougknox.com/xp/utils/MessengerDisable.zip
It's completely self-explanatory.
Regarding most fixes: If I'm not computer savvy, your instructions would scare me. How do I know you're not here just to destroy my computer? (which is not true) or how do I know it's not just a malicious script I'm loading (regarding the .vbs) -- also, if any problems do occur. It's always nice to be protected by a comprehensive Disclaimer =)
Once again, good job. I'll probably put one together myself for my site. Given the fact that these errors are a great annoyance when trying to get an application to work, just so you can communicate to your friends!
DISCLAIMER: BY FOLLOWING MY ADVICE YOU AGREE TO HOLD YOURSELF RESPONSIBLE FOR ANY DAMAGE CAUSED AS A RESULT OF FOLLOWING MY ADVICE (IF ANY). BY AGREEING TO THIS DISCLAIMER YOU NO LONGER HOLD ME AT LIABILITY FOR ANY DAMAGE TO ANYTHING OF YOUR PROPERTY OR ANYONE ELSES PROPERTY.