iTunes won't close on Windows XP (SP2); uses 50% CPU

UPDATE 6/16/08: If you run NOD32 as your antivirus program, you might want to try this little trick (thanks, nka!): This article describes how to add iTunes to NOD32's exclusion list if you're running Windows XP. If you're running Vista, simply upgrade (free) to the new version of NOD32. If that doesn't work for you, try what I mentioned on the 5/16/08 update below.

UPDATE 5/16/08: Astute readers point out that simply disabling the Bonjour service as follows should solve the problem: Start > Run > services.msc > Double-Click on Bonjour service > Stop it > and in the Startup Type dropdown list, select Disabled. Then disable sharing in iTunes.

If you're reading this, it's probably because you're running Windows XP and iTunes won't exit/close/quit on its own unless you force it to quit (i.e., End Process in the Task Manager). You've been searching for a solution, but have found none.

Maybe you're just about to give up hope. I know I almost did. But then I fought back--and found an answer. Fair warning, though: it's a little extreme. You can experiment and cut out certain steps as you see fit, but I can't guarantee you'll enjoy the success I am currently enjoying. It's up to you.

And so, without further adieu, here's how to get iTunes back up and running (and closing on its own) once again:

0. Read through these instructions to have an idea of what you're going to do before you decide to do it.

1. Add/Remove Programs

2. Remove iTunes (In addition, I removed ALL Apple products, just to be safe, listed as 2.1-2.4)
2.1. Apple Mobile Device Support
2.2. Apple Software Update
2.3. Bonjour
2.4. Quicktime

3. Delete all leftover Apple-related files from C:\Documents and Settings\*
3.0. Note: do NOT delete anything in C:\Documents and Settings\YOUR USER NAME HERE\My Documents\My Music\iTunes (or wherever you store your iTunes music library file. iTunes will automatically use these files again if they're in the default location.
3.1. C:\Documents and Settings\All Users\Application Data\Apple Computer
3.2. C:\Documents and Settings\YOUR USER NAME HERE\Application Data\Apple Computer
3.3. C:\Documents and Settings\YOUR USER NAME HERE\Local Settings\Application Data\Apple
3.4. C:\Documents and Settings\YOUR USER NAME HERE\Local Settings\Application Data\Apple Computer

4. Delete all leftover Apple-related registry entries from the Registry
4.0. WARNING: Make a backup copy first. If you don't know much/anything about the registry, I'd skip this part unless you feel ballsy and like living on the wild side.
4.1. I use a tool called jv 16 PowerTools 2007 to make this task a little more efficient. Otherwise, it's time to just use the Find funciton of the Registry and do the dirty work.

5. Restart (save how-to guide, if you're writing one at the time) ;)

6. DO NOT UNDER ANY CIRCUMSTANCES WHATSOEVER enable the "Share my library on my local network" feature. This will result in iTunes exhibiting the lock-up you experienced upon closing, and it is impossible to recover from this and reset your iTunes preferences unless you follow the painful steps above. This is about my 3rd or 4th time doing this, so I'm confident this will work for you.

Good luck!