Back in Windows 7 and before, you could change the system font through an easy-to-use dialog window. In Windows 8, Microsoft took that window away and made it near impossible to change the system font, though there was a working Windows 8 Font Changer tool.
Now, in Windows 10, we're out of luck. Microsoft still won't let us change fonts and there's no font-changing tool to use. The only way around this is to edit a few fields in the registry, but this can be risky. One mistake and you might cause irreparable damage!
Do not attempt to do this without first backing up your registry! If you don't save a backup, you won't be able to revert the changes. We hold no responsibility if something goes wrong.
If you're really sure you want to go through with this, here's what you have to do. Open the Start Menu, type regedit, and use that to launch the Registry Editor. In the editor, navigate in the left sidebar to the following:
HKEY_LOCAL_MACHINE \ SOFTWARE \ Microsoft \ Windows NT \ CurrentVersion \ Fonts
Then, in the right panel, look for every item that starts with Segoe UI. For each one, right-click on it, select Modify, then clear the Value Data field, and click OK. Continue until you've done every Segoe UI item.
Now navigate in the left sidebar to:
HKEY_LOCAL_MACHINE \ SOFTWARE \ Microsoft \ Windows NT \ CurrentVersion \ FontSubstitutes
Now right-click in an empty area in the right panel, select New > String and call it Segoe UI. Then, right-click on the newly-created Segoe UI item and select Modify. For Value Data, enter Tahoma (or whatever other font you want to use).
Close the editor, sign out of Windows, and sign back in. You should now see the new system font.
How do you like Segoe UI as a font? What other fonts would you prefer to use as a system font? Tell us in the comments below!