Q: Iphone 7 won't connect to iTunes on computer

By "the latest version available" do you mean iTunes 12.5.1.21? If not, are you running Windows XP or Vista?

I have the same exact issue, and yes I am running Vista latest 12.1.3

If you are running Vista then you cannot be running the latest iTunes version which is required to sync and restore an iPhone 7.

Windows Vista cannot run iTunes 12.5.1.

If your computer supports it, its suggested to update to a newer version of Windows. At least Windows 7 to be able to install iTunes 12.5.1 which is required for an iPhone 7.

I Have this problem, I'm running iTunes version 12.3... and when I open it it says a new version 12.5... is available to download. It takes me to the download page and downloads a file. It all installs apparently fine but when I open iTunes again I'm still on 12.3.

The general troubleshooting advice when iTunes fails to install properly (and reinstalling or repairing it does not work) is to remove not only iTunes but all related components, reboot, remove the target installation folders and reinstall.

See turingtest2's excellent iTunes for Windows Troubleshooting Guide at:

Troubleshooting issues with iTunes for Windows updates

for the necessary steps.  Especially see the Removing and reinstalling iTunes and other software components and iTunes installers sections.

Sir, this has been happening to me and I am running Vista.  Any thoughts on how to fix this?

As already explained, Update Vista to at least Windows 7, and download the most recent version of iTunes then.

Vista cannot run iTunes 12.5.1 and as such cannot sync with an iPhone running iOS 10