93 urS4: no turn over, no start, no jump (MORNING AFTER)

[Dave C.]

Depending on type of cable clamps, etc, it can be difficult to get a good
connection under the hood.  I would attach jumper cables directly to the
battery rather than use the post under the hood.  

Another thing to be aware of is that low temp will decrease battery voltage
a lot.  A temp drop from 70 to 0 (F) corresponds to a drop of about 0.6
volts... even a new battery will be taxed.   At 11.9 volts many of the
accessories will still work but the starter will not.... BTDT yesterday.
Merely taking your battery indoors and letting it warm up may increase
voltage enough to start the car.  With the kind of cold weather you have
there, and knowing your battery is old, I would suggest the first order of
business would be to buy a new battery.  

Also, check the tension on the alternator belt..  slipping belt decreases
charging performance.  Keep in mind you are probably running more
electrical accessories this time of year... the defroster is a big
electrical user.     
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Dave C.