Blue244 raises a good point. "White" engines can loose compression through the valve seats and the "no-start" condition is exacerbated by fueled down piston rings, soaked plugs and a gradually weakening battery.

My recommendation: new plugs - not tri-tip style you have or any platinum or laser fancy shmancy plug. NGK BKR6E. Newer platinum, iridium, etc plugs are not able to "clean" themselves as well as traditional plugs, and that's what you need. While the plugs are out, crank the motor to clear the combustion chamber of fuel. Reinstall plugs. Make sure you have a tip-top battery. I would even put a strong charger on it while you crank it. You will have to crank the engine over upwards of 30 seconds. Don't worry. And don't touch the accelerator. Little by little you'll hear one cylinder fire, then another, then another. Process will have to be repeated. Eventually, it'll start.

Now the fun part. Valve seats get some buildup with miles, especially with prudent driving. Valves in white motors will begin to "spin" in their guides upwards of 4000 rpms or so. So you need to take it for a "hell ride" aka "Italian tune-up" Drive for 10-15 minutes in a low gear so that the engine is screaming along above 4-5000 rpms. You will effectively be performing a valve job. You won't hurt anything and you'll be rewarded with a smoother, more easily started motor.

Good luck.