The 5275 is the correct belt (I just bought a new belt yesterday from Sears). Changing the belt is pretty simple. Remove the bottom of the vacuum cleaner by sliding over the 2 latches (middle of the bottom) that are slid under 2 screws. Then press in the 2 tabs that are on the sides and pop the bottom out. This should expose the brush and belt assembly. Since your belt is assumably broken, just pull the brush/agitator out from its slots. (While you have the brush out, pull off the metal end caps and clean out all of the hair, etc.) Put the bare floor/carpet selector to the carpet setting (UP). You should see 2 metal rods, put the belt behind the back rod. Place the other end of the belt over the brush and stretch it until you can slide the brush back into the slots (don't worry, you have the right belt.... it may seem like the belt is too small, but you do have to stretch it). So.... the belt should be connected to the brush and the back rod with the inner rod inside the belt, but probably not touching it. The inner rod is for placing the selector to bare floor and it picks up the belt so that it does not activate the brush. Just reassemble the vacuum and you should be good to go. I know the description is a bit rambling, but a picture is worth a thousand words. Hope it helps.
Derek, January 2006