Vacuum Cleaner sucking dirt out of the cannister...

Question

I just bought a Hoover Vacuum cleaner from a garage sale.  When I tried to use it I noticed nothing was going into the cannister.  I checked the vacuum and found it to be clogged.  I took it apart and cleaned it out.  When I tried to vacuum again there still wasn't anything going into the canister.  I took the cannister off and turned on the vacuum.  When I placed my hand over the hole where the dirt is supposed to go into the cannister I found it to be sucking in air instead of blowing it into the cannister. 

If you can help me with this problem I would appreciate it.

Thanks,
Mike