Engine won't fire up! Options

[X_RunnerGT]

So recently my car stopped wanting to start. I turn the key and the starter cranks continuously,but it won't turn over? I left my key in the ignition, turned, yesterday and it fired up. Once it's started and it's been running for a while it'll start, but now nothing? Any ideas about what I'm dealing with. I've been told the timing belt, the fuel pump, fuses, which from the ones I've checked are all good. Any help would be appreciated...

[VavAlephVav]

hmm that makes me think computer.
Bad electronics will work one minute and not the next, and then start working again all depending on what the humidity is like.
It may be worth it to pull the PCM out (it's under the dash in the center). If you open it up and carefully examine the circuit board and components in there with a flash-light there is often some nasty looking gunk oozing out of one of the capacitors.

Or you've got a corroded/broken ground wire somewhere.