Since all the lights go out on attempted start - look first at the battery
terminals for corrosion. Take them off and clean if necessary. How old is
the battery? 3 to 5 years is about normal lifetime.
Check the battery charging with a voltmeter when running - should be about
13.8V and about 12V when off. With engine off, measure battery voltage (at
the battery) while switching on headlamps. If the voltage drops more than
.25V, battery is bad.

There is another possibility in that the starter is shorted or the engine is
somehow jammed from turning over. Either of those will cause an enormous
cranking current that will dim the lamps. Don't sweat this yet until the
battery and terminals are checked first. If the starter needs replacing- it
will come with a new solenoid.

If you know someone with one of those jump-start battery packs - try that
out to see if it starts any easier. Make sure you get good contacts on the
clip leads. (I bought one a couple of years ago when I got stuck in the
boonies with a dead battery and a sick wife)