97 Diamante disconnected battery now won't start!
 

So we bought a 1997 Diamante with 80,000 miles a month ago. It's been running great, no problem.

The other night I couldn't get the driver door to open with the key (iced up--we're in MN). So I went to the passenger door and opened it with a key. The alarm system started going off.

I didn't know what to do to shut it off--(Yes, I have learned since that it will shut off in 3 minutes on it's own. And I didn't think of putting the key in the ignition)--so a visiting friend went out there and did a disconnect on the negative of the battery.

It hasn't started since. We reconnected the battery, and all is tight. Husband had pulled out horn fuse, but he put that back in.

What the heck do we do!?