Why wont My truck start?

i have replaced the silenoid under the hood and i am getting fire to all points and battery is good(even tried jumping it off but non responsive,and tried crossing the bolts to force a start but no luck) but it still wont start ,i turn the key and it doesnt do anything a small quiet click can be heard and when i turn the key all the lights go out untill i release it,also o noticed guages acting funny (fluxuating sparatically) and the odometer dissapeared other day but reappeared.i am going to deal with the starter today and if it still wont crank ,any ideas what it is. it is a 2000 expedition eddie bauer.