My Dyson DC07 was make a LOUD noise when using it. It also would not pick up. We replaced the first belt thinking it was the one you could see. Same noise. Replaced the inner belt and the noise is no longer there, however, it will not pick up while in carpet mode. Looks like the brush is not spinning. It just pushes the dog hair forward. No noise anymore though.
maybe the carpet mode gets stuck so the brush wont spin, turn it on its side and push the bit of plastic thats connected to the carpet mode, ON, AUTO, OFF. i find that it will likely get stuck again so you might need to do this every time you put it in carpet mode
slunky
January 2010
check here www.dysonmedic.com will take you through strip down/rebuild with words and pictures you may have over looked something,
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix vacuum cleaners.