Evening All

Just wanting to pick some brains really, Ive got a 98 v70r auto which this morning decided not to start.

Drove the car last night fine and went to its this morning and it just cranks and cranks. I noticed as soon as the ignition is put on the rad fan kicks in. Left the car for a couple of hours and tried again still the same. Rad fan kicks in, car cranks but doesnt start.

Came home from work with 2 code reader and some tools to check spark and fuel, but no faults stored in the ecu and now the car starts! fan doesnt kick in untill upto to temp but i cant get my head round what happened. Any suggestions or thought would be great as i have 2 small children and dont want to get caught out

Thanks in advance