not starting..

i have a 1990 f150 with the 300 straight 6 in it, when i bought it, it wouldnt turn over from the key, so i replaced the the ignition where the key goes in and the electircal part of the igniton on the column, i also replaced the solenoid and it still wouldnt work unless i crossed the solenoid, now it wont even do that, when i try to start it, it makes likea vibrating type noise and dosnt turn over. ive tried bypassing the solenoid straight to the starter too and the same thing happens. i tried a new starter and still the same thing. im completly lost could someone help me please.

check the grounds.

yea i checked every possible ground, it still does the same thing, i pulled the new starter off too thinking maybe somthing was jammed and i saw that a few of the teeth are scarred, and i put it back in and its doing the sme thing again, is it possible my flywheel is seized? help me someone i need to move the truck in 2 days cause im moving and cant leave it behind.

check the connections at the battery and the positive battery cable. did you try turning the engine over with a breakerbar to make sure the engine's not seized?