Hi,
Mine has been nothing but trouble. I had the same problem and its something to do with the filters.
Does the red light come on when it over heats as this is an indicator that the filter needs cleaning.
You need to wash them as shown in your manual.
Also I found that the suction was very poor using the plastic box so I changed to the hepa bags and the difference was amazing.
You need to contact hoover and they will send you a small part that allows you to use a bag instead of the box, also it was a free service.
Hope this helps.
Snooky
January 2008