how can i fix my waher?

Lisafixhelp. Quite a surname! Anyway, If you have the back off and the large drum belt is still attached, then it sounds like the 'brushes' on the motor are worn and need replacing.
Make sure the machine is unplugged, before touching the insides. At the bottom of the machine you will see a lump of silver metal which the belt for the drum goes round. This is the motor. If you can, tilt the machine back onto it's back feet, prop it up or have someone hold it whilst you look under. Take a piece of wood or the handle of you screwdriver, and on this visable side of the motor, (opposite side to the belt pully), you will note 2 black plastic units on the end of the motor. Tap these gently with the wood or screwdriver, then return the machine to it's four feet. If the machine is turned to "spin" and it works, those two Brush units you tapped need replacing.

Davymac
July 2009