Hi pats87 .... and welcome to the Linux Mint forums
There can be (for some people) a problem with the slideshow during the install.
Although I think that problem usually appears at the start of the installation, not 90% through it.
So, it may not be your problem.
Still .... you could try this first to rule out the installer as being the issue.
Boot your live usb.
Before you click "Install", open a terminal and type insudo apt-get remove ubiquity-slideshow-mint
When finished, close the terminal, then click the install icon.
You won't see any of the slideshow during the install and hopefully it will then finish. But, it hasn't worked for everyone.
Could also try installing as above, without being connected to the internet (if you haven't already tried that).