.fon is a bitmap font file format used by Windows 3.x through XP. Some driver installers incorrectly delivered configuration dialogs as font resources. Thus, when a program calls msdlg874fon and it’s missing, you’ll get an error like:

To safely secure your copy, rely on these legitimate channels:

This is the most common cause. If you are using a burned CD-R or an ISO file that was not verified correctly, the msdlg874.fon file might be slightly corrupted. Even if you do not speak Thai, the Windows XP setup routine attempts to copy every file listed in its manifest. If one fails, the setup halts.

host unmodified ISO images of Windows XP (such as the "VL" or Volume License versions) that are generally considered safer than random "free 101 install" links found on search engines. Microsoft Learn Common Installation Issues

: Let the blue setup environment load the default system drivers. When the welcome screen appears, press Enter to set up Windows XP.

Are you installing this on a or on retro hardware ? Do you need assistance finding clean, verified ISO hashes ?