'Ave ye updated to the latest version of FH? If not, reinstalling the old version won't work. Also, be sure to reset and send all y'er old characters home because the old maps are no longer in use.
Also be sure to delete ev'rything related to FH before reinstalling. Sometimes pesky copies escape and float around in y'er computer, causing havoc to the game. Particles are another reason the game may crash if ye didn't do a complete reinstallation, so be sure to check y'er particle folder f'er "_0" files.
If ye 'ave updated the game, check y'er My_Objects folder. Some old object files no longer work with FH, so if ye've been saving objects, 'tis best to remove them and place them in by groups of [insert desired number here]. Then, open the game to see if it crashes. Ye can deduce what files are messing with the game from there.