If you just download the updated version without uninstalling the existing install then you shouldn't have any problem. It's pretty efficient normally in copying everything over to the new version. Just click 'Help' then 'Check for updates' It should all be automatic from there..
Make sure you make a restore point before starting then, If it all goes belly up again, just do a system restore. Everything should be back to normal then.
Hope you have a trouble free install this time....
