From http://support.microsoft.com/support/kb/articles/q133/7/25.asp
1) the Fonts folder must have the "System" attribute SET
use explorer to look at it and set it if its not checked
or
in a command prompt type...
cd\windows
attrib fonts +s
Shut down and restart Windows.
2) The Fontext.dll file may be missing or damaged
Restart Windows in MS-DOS mode.
Change to the Windows\System folder.
If the Fontext.dll file exists, rename it Fontext.old.
Extract a new copy of the Fontext.dll file from the original...
...Windows disks or CD-ROM to the Windows\System folder.
Restart Windows
3) The Desktop.ini file may be missing or damaged
To see the file, open an MS-DOS session and view the Windows\Fontsfolder.
Restart Windows in MS-DOS mode.
Change to the Windows\Fonts folder.
If the Desktop.ini file exists, rename it Desktop.old.
Extract a new copy of the Desktop.ini file from the original Windows
disks or CD-ROM to the Windows\Fonts folder.
(Sometimes when I cut and paste URL's it looks ok to me but once the answer is posted, an extraneous space will have crept in. Make sure you delete any extraneous spaces or the page won't load).