NOW we know why we sneeze: our nose needs a system reboot.

Research published in the online FASEB Journal likens a sneeze to Microsoft Windows' infamous blue screen of death - an involuntary reset of the nose's sensory system.

The finding offers new hope to people with disorders of the nose, such as sinusitis, which may be a result of a reboot failure.

Dr Noam Cohen of the University of Pennsylvania says when our nose becomes overwhelmed, the pressure forces of the sneeze resets the biological environment of the nasal passage so it can once again trap particles breathed in for analysis.

Microscopic hairs on the cells that line the nasal cavities trigger the sneeze.

Dr Cohen and his colleagues studied how the nose cells from mice cleared mucus. When exposed to a puff of air to simulate a sneeze, the cells biochemical responses were seen to reset.

The experiments were then replicated on human nasal tissue. Tissue from people with sinusitis did not respond to the artificial sneeze in the same way as normal nasal cells did.

Dr Cohen said people with sinusitis may sneeze more regularly because their nasal environment is not being reset properly.

The editor of the journal, Gerald Weissmann, said he was confident the research would help find new treatments for chronic sinusitis.

" (But) I'm far less confident in our abilities to resolve messy computer crashes. We now know why we sneeze. Computer crashes are likely to be a mystery forever."