My friend has a 94 Probe SE and on friday her.

My friend has a 94 probe se and on friday her uncle installed an aftermarket radio in the car. Today it would not start at all. She replaced the battery, wires, spark plugs, starter, starter relay fuse, and alternater and when she turns the key it gives her 1 click at the fusebox under the hood but doesn't start. All of her ground wires are connected also. What could be the problem cause doesn't want to keep buying the wrong parts?