Does Not Spin.
This most often occurs if the lid is stuck open or the switch that tells the machine if the lid is open may be broken. Try pushing down or pushing in the switch that moves when the lid is opened. If the machine doesn't turn on then it's probably not the switch that is failing.
Make sure the machine has power. Check your breakers.
You could have a bad timer or a bad computer.
If you have a front-loader machine, you may have a clogged drain. Front-loaders won't finish their cycle if they can't get rid of the water.
Does Not Drain.
You may have a clogged drain.
The door may be open, or the switch could be broken.
You could have a bad pump.
The computer could have a problem.
Does Not Agitate.
Your agitator may be bad. This often happens from overloading or age. These parts wear out and yours is old we recommend having a repairman look at it and possibly replacing it.
Timer may be bad. If the timer breaks the cycles won't complete.
The transmission or motor could be the problem.
Making Loud Noises.
Belt may have broken or motor coupling could be malfunctioning.
Pump may be bad.
Transmission may be broken.
Motor may be bad.
If you have a load in the machine, make sure you don't have an unbalanced load. Try to put your clothes evenly around the tub. I know it's not fun putting your hands in hot or cold soapy water, but this is often the problem, and easy to fix.
Your springs may be bad. Machines have springs to keep the tub from flying too far back and forth. When they get old or rusty they break and need replaced.
Water inlet hot or cold may need to be fixed. Hoses get old and so do the connections. If you have a lead on the inlet hose it's not too hard to replace. Turn off the valve first and get a replacement at a home improvement center.
Maybe it's your drain hose. Check to make sure the drain hose is in the drain pipe.
You could have a busted pump, valve, seal or coupling internal. Call a repair professional for something like this.