Hello JackT44,
It sounds like you have taken some photos and videos on your phone and want to open them on your PC. You will not be able to access them from the backup of the device itself in this manner. What you should do is import them to your computer from the device with the tool that Windows has built into it. This article will help you do that:
Import photos and videos from your iPhone, iPad, or iPod touch to your Mac or Windows PC
If you cannot then this article will help you troubleshoot that:
If you can't import photos from your iPhone, iPad, or iPod touch to your computer
Thank you for using Apple Support Communities.
Take care,
Sterling