safe mode doesnt load many drivers or application helpers. You may have several word and photoshop helpers loaded that may be locking the fonts. Windows itself will lock a bunch of them .

You may be able to delete via the Control Panel > Fonts option , select the file and use the menu File >Delete. It is meant to be a deferred delete which requires a reboot to take effect.  This is windows XP but should still apply to vista or win 7.