Which version of Photoshop are you using and which exact font do you find trouble using?
What all font kits(like Suitcase) do you have installed?
You may also simply post the system info from Photoshop Help>System info menu here, and we'll figure ou the rest.
I feel your pain. I have experienced the same thing, many times but it was always my error (and mostly on previous versions)...when scrolling to look at fonts and how they look with your text, it's only a 'preview', so until you commit the font, it keeps reverting to the original or last selected font. It's so frustrating....especially if you have LOTS of fonts and you've scrolled far down the list and weren't looking at the font name you would like to use.
If you're using your arrow keys to scroll and not highlighting the text, you'll run into more issues but it's still possible to do it that way. just make sure you either hit the enter key or highlight the text and hit enter to commit.
I am using whatever is the latest software and newest update, only downloaded the program less then 30 days ago. I don't have anything else installed.
I am using whatever is the latest software and newest update
Please state the exact versions as indicated under Help > System Info for example.
What is the Font Preview Size setting?