Microsoft has confirmed that Some users have found that certain fonts they use are missing after upgrading to Windows 10.
here is post for same Some fonts are missing after upgrade
Please try to download and Install all Windows Font from this link, this might help.
Most answers about this problem has been anything from re-adjusting the toolbar and the taskbar to reinstalling the software. Actually, that worked for one person who said it reinstalled on his 3rd try.
Here's my standard answer for this problem, but first I need to say, Adobe does not support versions before PSE13. But I will do whatever I can.
There are resets for this PSE and in Windows 10, too. I will not drag you into a SFC reset which is merely the same thing, and it would need lots of commands in a Windows Power Shell.
In PSE, open any image. In PSE, on the far-right is a question mark (?) and next to that, is a down-menu with "Reset-all-tools". Click that. That will reset everything and it should be good for now. With a corrupt program I doubt if this might appear.
If that doesn't work, go to Windows 10, go to All Programs on your Start button, find Settings. Click on System. Click Apps and Features. Your applications will load on the right. Click on your application to highlight it and then, if you see a blue hypertext link below it that says "Advanced Options" - click that. On the next page on the left, is a RESET button. Click that. You're done with this one. Note: If you don't have a blue hypertext link below the app, each app may give that opportunity only once, and if you don't have it, it's not available to you. Sorry.
there is an update that knocks out a driver, I reinstall it. Another way to do this is to uninstall the program and reboot, and reinstall it. It works even if it takes 3 times to reinstall it. Do not give up.
You can disable the update, but it will come again. If you want to do this: go to "All Programs" in your list of programs on your start button, go to Settings, go to Update History, on the next page you may click on updates with the same date as the day this happened to you, and remove it. You're not losing anything, it will come back again.
There is another reset as a last resort, and it may take a little work and I usually skip this one:
Go to Settings, Update, then click on Recovery on the left. THIS is only if you want to go with the most hard way to get that program back. This gives you choices: You can restart Windows to begin again, which will load it all over again as if new to defaults. It not harm your apps or files.
OR - You can go back to an earlier build with the Restore feature but you may encounter the same update in the future that may do harm again, and anything you did with files or apps will be canceled. Any other choices are not good, and I never recommend this for corrupt apps.
Now I've given everything. My choice would be to reinstall your PSE 12. My higher recommendation is for you to stay current with the latest PSE15.
PSE15: You can run your old PSE along with it, but launch the older version before PSE15, or the PSE15 will freeze upon its launch. OR you can delete the older version (I would) and reboot, then install PSE15. It's much like PSE12, except the re-do and un-do buttons are on the top instead of the bottom. AND, not like Photoshop CC, there is not a subscription for PSE15. Go for it!
Steve Lehman, Windows MCSE responding