Q: Windows 10 and iTunes sync problem

Correct.  All parts are installed, all drivers are correct and functioning properly (according to Windows,) the phone shows up in iTunes (even says that it's running the most up to date version and will check again in a few days.)  The Sync button is grayed out, I can't press it.  I also can't manually back the phone up there; when I press that button, it goes gray for just a second then comes back, and nothing happens.

When you plug your phone in, does it still bring up the Windows prompt to import photos etc like it used to?  Cause that doesn't happen for me either.

It lets me make those changes (adding a playlist, for example,) and I can hit apply.  It looks like it does something for a split second, then nothing.  The sync button never shows up.

At the suggestion of a friend, I looked up my laptop on the manufacturer's website, to maybe see if there are Widows 10 drivers that I might need to upgrade.  Dell is not developing or testing Windows 10 drivers for my particular laptop (which is 6ish years old.)  Any confidence that this is the root cause of my issue?

Nothin there helped either unfortunately.

If I don't say it again, I do want to thank you for your ideas, I really appreciate the help.

So I tried an experiment that gave me some hope, but not sure where to go next.  I plugged my girlfriend's 4S into my computer (it had never been before.)  Lo and behold, it did some of what I hoped it would: Windows brought up the small pop-up in the lower right corner (something like "What would you like to do with this iPhone?  and the options of importing photos and videos, going to dropbox, etc)  Her phone gave the "trust this computer?" prompt and the iTunes recognized her phone perfectly.

The Sync button was still grayed out, but all of the sync checkboxes (Automatically sync this iPhone when plugged in, Sync this iPhone over WiFi, Sync only checked songs and videos) were all unchecked, and the Sync checkboxes under the Music and Video (etc) settings were unchecked too, so that doesn't surprises me that the main Sync button was grayed out on the main page (iTunes wasn't telling it anything that it should be syncing, so it makes sense that you can't sync anything.)  I didn't change any of them for fear of it actually working and erasing her music.

I ejected and unplugged her phone, and plugged it back in, but this time (and all others after) it didn't bring up the Windows prompt, so seemingly didn't work anymore (and my phone still didn't work.)

My thought is that her phone hadn't been associated with my iTunes before, so it had no problem working correctly that first time, whereas the times since it was associated, all all times with mine (which is obviously associated,) it screws it up somehow.  What do you think?

Is there a way to disassociate my phone from my iTunes?  That would at least give me the opportunity to try the same experiment.

Gah.  So If I go into the View Devices in Control Panel and uninstall the iPhone, unplug it, then plug it back in, I can get the "Trust this computer?" prompt on the phone.  That seems like progress?  But with hers, iTunes itself had a prompt that was similar, and said something like "go the phone and say Trust this computer."  That isn't happening for me.  And of course the Widows prompt to import or whatever doesn't come up.  I'm not signed into my Apple account on iTunes, thinking that might help - it didn't.  Why did hers work and mine doesn't?!?!?! I Could throw something.

This at least says to me that my laptop is capable of doing this, that it isn't a problem with drivers not being available as I thought possibly the other night.  That leads me back to my phone itself being the problem.  But iTunes recognizes it, can play and view data off it, Windows sees it fine (I can explore the pictures on it through Explorer)  I would think if there was a problem, it wouldn't be able to do everything, not just sync.  But Windows DOESN'T recognize it enough to ask what to do with it when I plug it in.  So maybe there IS a Windows problem?

Does Apple read these forums, or is it all private users?

Update:  I did a clean install of Windows 10, and it fixed everything.  It appears the upgrade messes a bunch of things up (iTunes wasn't the only program having issues after the upgrade, but they're all fixed now.)