I just installed a new update for my Windows 10 laptop. Fallout was playing normally at first, than crashed to desktop. When I tried to launch it again it said it had a run time error: missing string. Uninstalling and reinstalling did not help and now Fallout 2 won't work either.Has anyone else run into a similar problem? Any tips on how to fix?

Can you show a screenshot of the actual error?

Let me guess, your Windows build version is 1809 or higher? If so, there is a trick which sometimes works. Enable folder protection feature, add your Fallout executables to the exclusion list, disable folder protection, reboot. From this point if game starts to behave badly again, just reboot. Well, in case if I am right and it's really buggy feature of the new build creates an issue.

Also make sure that you are not trying to install into the Program files directory. It's a common advice anyway. And newer builds of Windows 10 became much more sensitive about this.

And the last but not least: it wouldn't hurt to check your OS and your installer files with an antiviral software. Sometimes infection effects coincedencially manifest themselves after big Windows updates.

If none of the above applies, the best solution would be to rollback to the build 1803 and disable Windows updates completely. Because guys at Redmond have done something really wrong this time and they don't hurry to fix this specific issue. Newer builds often prevent even some database services from accessing thier data files. And none of the available on the Internet solution steps really help.