I can't eject ("files in use by another application") Windows/Vista Issue?

OK... so in the grand scheme of things, this really is NOT the end of the world... but it sure is super-annoying!! This is my first every Apple product (took a while to get on the bandwagon) and I was hoping for more stability and ease of use... I've called AppleCare several times and they can't help me figure this out... according to them it's a Windows/Vista issue (which DOES seem likely). I'm running Windows Vista Home Premium on a Dell Dimension E521.

Here's how it goes... I plug my iPod in, which opens up iTunes and it syncs fine. I wait until the top of iTunes says "sync complete" and the face of the iPod simply says "Connected". Then I click on the "eject" button next to the iPod listing in iTunes. It pauses for a moment, then I look down and the iPod suddenly has those syncing, circular arrows, moving again and it says "Synchronizing- do not disconnect". And then a few moments later, iTunes gives me a pop-up that says " XXXX ipod cannot be ejected because it contains files that are in use by another application"

So obviously, something else is connecting to the iPod and preventing me from ejecting it using iTunes, but I have not been able to figure out what it is!

Since it's something on my machine, I have tried the following:
- shut down AntiVirus (TrendMicro Internet Security 2008)
- turned off Windows Firewall
- went through all the programs running in the task bar and turned them off
- opened up Task Manager and turned EVERYTHING else I could see off

None of the above have made any difference. The workaround that Apple gave me was to go into Computer and then right click on the listed drive and select "Safely Remove" which usually works (the times it doesn't work, it gives a similar message saying the device was being used by another application and can't be removed, try again later). But 90% of the time it works.

I use that or the Eject option when I right click on that drive (not sure the difference, they seem to do the same thing). The workaround works, but I'd sure LOVE to get iTunes to be able to eject my iPod!!

Here's what I've done regarding this iPod and iTunes:
- reset the iPod
- restored the iPod
- uninstalled and re-installed iTunes
- selected and unselected the various things I'm syncing (currently: Music, TV Shows, Podcasts, Photos) to see if it was one of them causing the issue

NONE of the above has made any difference (and I've done each about 2-3 times, ZERO exaggeration).

I've called into AppleCare about half a dozen times now, hoping to get that one brilliant tech that knows more than the others... but no luck yet... so I thought I'd try this forum to see if one of the brilliant posters here can help me sort this out.

PLEASE- ANY help you can provide (or even just point me in the "right" direction of how to determine this) would be GREATLY appreciated!!

Thanks so much in advance,
SC