It is quite possible that all your problems come from the Trash Can.
Especially when you go to install any program you have to go to the trash can, propertis, and check ALWAYS DELETE inmediately.
And after this, install.
Yesterday I firefoxDD Drag & drop, failure installer for this reason. Reinstalling, make sure the trash can, delete the old folder firefox, and all were problems.
It would be good that the new version would have on the trash can an automatic compression to zip files to, lost propertys in files. Because in reality the current paper is a Move, and that printers have lousy memories.
For now what I do is cancel the trashcan, if I remember.
Saludos