Check to see if the block heater is there first,maybe just the cord is missing.It should be in the pass side of the block,at the rear,just above the starter.If you slide in underneath,and look up,you should be able to see if it's there.If it is,get a cord and see if it works.
If it's not there,you could put a new block heater in,or use a circulation heater.Block heaters seem to be more reliable,and do a better job.
Might want to check your glow plugs too,as that will make it hard to start as well.