I purchased my third Hoover upright self-propelled vacuum about two years ago and I'm definitely not as happy with it as with my previous vacuums.  My biggest complaint is that the on/off switch sometimes works and other times it does not.  I have taken it apart and cannot see what the problem is.  I even resorted to asking for help from my husband . . . always my last resort!  He can't see what is causing the problem either.  Now I sometimes have to un-plug it in order to turn it off.  I am worried that it's not safe to do that on a regular basis.  As I still have my old Hoover upright...