* Outside unit is running; in fact, the line froze from the unit to the siding. I turned the unit off today to allow it to thaw, which it did, but still issues.
* Electric air, gas heat. In the attic the furnace lies next to the air ducts, there is a switch on the wall that turns the furnace and A/C off.
* There was cold air "leaking" from the side of the furnace, which seemed odd to me at least.
* The house sat for a year without being occupied, so I wonder if the vent is somehow blocked.

I read somewhere it could be the air handler. I admit I am a noob to owning an A/C unit, and although I have been successful at fixing other issues around the house as they have arised - many times figuring stuff out as I go - this one has me stumped. Any advice would be appreciated. I am pretty sure the answer is either really simple or really expensive.

Thanks!
Jeremy

Have an AC technician come and check the system out.
Ask neighbors for recommendations.

The system could very well be low on refrigerant.

Do not try and run it, especially if ice is forming al the way to the outside compressor.
If refrigerant liquid gets back to the compressor it will be destroyed.

Turn on the fan, but leave AC off to melt ice off the evaporator and make sure all of your windows and doors are closed. Some newbies (myself included) have left a few windows open before while trying to get the heat out, and turn on ac to get the temp down. That combo doesn't really work well :)

Make sure you see water trickling out of the drain. If not, thats a problem. If the piping feels lukewarm (not hot or cold, depending on where you touch it) something ain't right.

A correctly operating system should still not be frosint to the condenser.

An open window might limit cooling, but the drop across the coil (and air flow) should still be there.