This was weird but at last I fixed it.
Just for info: on my Windows 8 I could not uninstall the XVMSymbol font in any way, because Windows insisted to tell me that the font was in use by csrss.exe, that is an unstoppable system client/server service. Don't tell me wtf why. I even tried to delete the handle from it without success.
To get rid of the problem I had to:
- start an Administrator CMD
- manually delete all xvms*.* files inside the C:\Windows\Fonts directory
- remove all occurences of the font inside the registry
- install che XVMSystem correct font via the normal Windows procedure
- After this step, WIndows still didn't list the font inside the fonts window, and WoT didn't recognize them: I had to reboot and now all is ok.
... Thanks Windows, everything is always clear and straight.