Help please. Car won't start in cold.

[Graplr]

Okay, my 84 SD won't start. I parked it in a lot on Friday night with the temps in the 30s. Didn't get home until late Saturday night (much later than expected). By that time the temperature had dropped to -10F. The car obvioulsy wouldn't start. I pushed it up to a building so that I could plug it in. Wouldn't start. (I had some help jumping it so battery wouldn't die)

I left it plugged in overnight. Went back to it this morning. Still wouldn't start. Wondered if the block heater was working.

Had it towed to my girlfriends heated underground parking garage in which the ambient temp is about 60F. It has now been sitting there for around almost three hours. Still won't start.

The starter just turns and turns and it just won't fire up.

I'm at a loss for anything to try.

My next thought is to take of the filters and put some HEET or something in it, but if I'm in a heated garage it shouldn't matter should it?

I'm at a loss. What should I try to get it started?

Any help would be greatly appreciated!
Thanks!
-Ryan