Q: My new Iphone 6S will not sync with Windows 10 computer

iOS 9.3.2 requires that you have iTunes 12.4 installed on your computer. If you don't, then update it first.

1. What happens when you try?

2. Any error messages? Give exact text.

3. Is the iPhone recognized by iTunes?

4. If you're trying to backup to iTunes (should be encrypted) try a backup to iCloud, or vise versas.

5. When you sswitched to 6s did you restore it from backup of iphone 4?

On iPhone:

Try a simple Reset: hold down the Home and Power buttons until you see the Apple logo (10-20 seconds).

The next step would be a Restore, but doing it from backup is a lot easier than Restoring as new.

Restore your device from an iCloud or iTunes backup - Apple Support

On computer, if iTunes not recognizing the phone:

If iTunes doesn't recognize your iPhone, iPad, or iPod - Apple Support

Sorry to hear it's still not resolved.

iPhone can be synced to iTunes using Wi-Fi, but unfortunately it needs to be recognized to set this option up.

When you have the chance, take the iphone to a local Apple Store and have it tested.

And please remember that iCloud backups do not contain everything that's on your iPhone. You still need to  sync your data (calendars, notes, etc) and import your photos to whatever app you're using to manage your images and videos. Since Explorer sees the iPhone, you should be able to do that.

This article could possibly help. Worth a try perhaps as the Apple Driver is often the cause.

http://www.technipages.com/itunes-fix-iphone-or-ipod-not-detected-in-windows

yes, this article worked! thanks for the link

My pleasure felbus.... 

Glad to hear. You are welcome....  

Thank you! This worked for me!