Yes not a good idea, lol, trouble is can't even see that or any other forum to delete so looks like May have to start from scratch and lose the years of posts nightmare but my fault
--------------- Added [DATE]1420490555[/DATE] at [TIME]1420490555[/TIME] ---------------
It has blanked out all the categories and forums so can't even any category
Its done this in the AdminCP? Oh dear. Well before you go off and lose a years worth of stuff I would go and make a backup of the site & database. You still have those there or at least you should. Try these things just for giggles:
1. Hard refresh your browser. Or just refresh it.
2. Delete your browser cache & cookies.
3. Go into your AdminCp and go to Maintenance > Clear System Cache that will clear the cache and may bring it back.