I understand - no sound at all when you turn the key.
In that case, it's a starting system problem: Either the battery, the starter motor, or the switching / wiring that make the starter motor turn. Could also be that the alternator has died (or the wiring to/from the alternator), and so your battery was not being charged.
Jump-starting the battery is a low-cost way to see if you can get going. If you try this, be sure to let the "good" car run for 15-20 minutes with your car completely shut off. Then, with the good car NOT RUNNING, try to start yours. With luck, it will start, and you can at least get to a shop or to a friend with a voltmeter tester, to find the source of your problem.
Starting your (disabled) car with the good car STILL RUNNING can burn out the good car's alternator. A little-known fact, but true, as the alternator will try to supply 100-200-300 or more amps needed to start your car. Alternators are only built to provide about 60-80 amps (depending on model), which is why you can burn out the alternator that way. A good battery can easily supply 600 or even 800 amps.