lights off in one room, other rooms in the same circuit are fine, no GFCI, breaker not tripped
It's very typical for power surges -- either temporary shorts, or simply plugging in a high draw appliance for the first time -- to "blow out" a wire termination - typically at a receptacle or switch.

Usually, the blown out connection is a "backstab" aka back-wire connection.  This is one big reason we do not like backstabs on this stack.  Occasionally the failure can be in a screw connection (one very badly done) or a wire-nut connection (typically also very badly done, and likely secured with tape because the person wasn't very good at wire nutting, and had to hold it together with tape to keep it from falling apart). 

The failure must be at the last working outlet in the chain, or the first defective outlet.  The "chain" being the wire jumps from the breaker panel to this outlet.