Darn, that didn't work either. Thanks much though!
The symbols look like user coordinate systems (UCS). There are two possible solutions to hide them.
1. Mark them in your model browser and remove the visibility with the right mouse button. This solution can be saved.
2. Go to the "View" menu - "Object visibility" and remove the approbriate marking. This solution is only active in your session.
Unfortunately they are all still there:( I just can't figure it out. Thanks for trying though:)
Open this black part and under view menu is center of mass point button. Click on it, icon looks like BMW logo.
Which version of inventor is that? I've never seen it do that before.