Car will not start

1990 honda accord, 4 cyl. 215000 miles, manual transmission.
I have had a similar problem as another here. My car will not ignite, try to turn over, make a noise, nothing. There is plenty of power going to the car. Like a previous question I too have had the brake lights stay on while the car was off, but that has been several months ago. Just recently I started the car went 2-3 blocks away came back home and within minutes was back in the car and it would do nothing. I checked battery, starter, fuses, etc. I did notice on the back of the clutch that the plastic part that disengages the nuetral switch was missing. I fixed that where it will engage and did engage when using the clutch but still nothing. How do I check this part without spending 70.00 on a new one. Any other sugg.