CTD00P dryer - wont spin with clothes in, spins without clothes. HELP!!?

I have a Hotpoint CTD00P.
The drum spins and it is heating up.
But when I have some clothes in, the drum is not spinning, but I can hear the motor / machine is trying to work.
I have checked the belt, it seems fine and tight around the drum.
Would this be a faulty capacitor or etc? And how do I fix it?

Please HELP
Many Thanks