Close all instances of 3DSimED is open.
Open "Registry search and delete 2.0.exe" ("R.S.D.") - can be downloaded from earlier forum posts or just Google it.
Type in the search box "3DSIM", tick "HKCU" and "HKLM", untick "HKCR".
Click "Search", wait until "Delete" button is being active.
Tick on all entries which contains 3DSimED (don't tick entries for 3ds Max and any other apps)
Click "Delete". After deleting, close R.S.D.
Then Open Tras