My tools don't work anymore, help!
There are a few things that can make a machine not work properly.
The most common thing is that it won't plow/plant/harvest in blocks any more.
Go to
preferences located top right of your game screen. The icon looks like a wrench/spanner

:
Make sure '
remove space between fields' is checked if you have no gaps. (If you do have gaps on your farm, make sure "remove space between fields' is unchecked).
Also make sure you have enough fuel. Check your fuel indicator located top left of your game screen. This image shows 3,264,945 Fuel.