My 97 ford powerstroke was working perfect then went out and the thing wouldn't move but the reverse is still working could this be a sensor or something small

It could be a minor electrical problem, or possibly a bad first gear shift seolinoid. Check the electrical connections on the transmission for corrosion or possibly a broken lock tab on a connection. It may need to be computer diagnosed as electronic controlled trannys arnt as easy to diagnose without a proper scan tool.