The belt and deck were fairly worn, the drive belt was fairly worm with rubber particles being thrown on the the motor housing surfaces from wear.
The biggest problem with this treadmill was the fact that movers had done a poor job of partial disassembly and/or moving. Three out of four of the motor cover screw supports were broken to the point where the motor housing cover would no longer fit on the machine correctly, causing it to easily rub against the running belt or the front roller.
The front roller adjustment bolt was broken so that it could no longer rest securely in its proper position. The running belt tension was the only thing that held it in its position which was up against the frame making the front crooked.
Due to the age and condition the best solution is it’s time for a new treadmill. At a minimum the broken bolt needs to be replaced and the belt cleaned, lubed, and adjusted. However a new drive belt, running belt and deck would be highly recommended if it was the owners intention to keep this machine.