The spooler service can be turned on with a simple command from a cmd.exe window:
Net start spooler
If your spooler will not turn on then there is likely corruption on your OS that is blocking that service from starting. It might be a good idea to boot into safe mode and try to start up the service to see if it can work or not. If not then you are most likely looking at a reload since troublehshooting the spooler itself is not normally worth your time.
Normally when there is a spooler problem the spooler starts just fine on its own. That is until you send a print job to the spooler which causes it to crash. You can normally keep the spooler online and running by cleaning up the installed print drivers and printer objects in your printers and devices area. A good clean reinstall with the latest software will normally do the trick.