If the brush is turning when you switch on then it is blocked at the very bottom of the flexible hose.
You need to remove the full top plate (the bit with the height adjuster handle) there are four screws underneath, one in each corner, take those out.
There is a screw under the wheel carriage (just pull it down and you will see it.
One last screw, just to the left of the bottom right screw, just look in the holes, you will see them all.
lay the vacuum flat pressing down the height foot lever.
Just loosen the plate, pull towards you and it comes off easily, unblock, you might need a knitting needle or similar to drag the blockage out of the tube.
Check the belt is ok then replace everything...job done!!!!
Lot easier than it sounds, honest!
Bill, January 2008