Do you run the 64 bit version of Sweet Home 3D (look in About dialog box)? if it´s not the case, run again the installer and select the 64 bit architecture when prompted.
Ticket moved from /p/sweethome3d/feature-requests/1232/
The 3D models furniture and textures you imported in Sweet Home 3D catalogs are stored in folders described here. Maybe some clean up services removed them, but certainly not Sweet Home 3D installer. Note that all the furniture and textures used in a given home are stored in its SH3D file, so your existing homes should be still working.
Try "Recompute room points" item in the contextual menu of the room you want to resize.
What do you mean by it didn´t work at all? If your SH3D file is very large (more than 100 MB), try to increase the max memory used by the program following instructions at http://www.sweethome3d.com/faq.jsp#increaseMaxMemory
Please try with YafaRay renderer if it works better.
Reducing the size of the 3D view to zero will stop updates.
You can change the color of dimensions from version 7.2 and select all dimensions with Select Hide utility plug-in. If you want to hide dimensions, put them in a separate level that you'll make unviewable.