Cranks but will not start

First I changed the lower arm control because it broke, then it stalled out a couple of times, it's cranked but won't start, I changed the camshaft valve, and all three ignition coils, I have power but no spark, I checked all the wiring, the fuses and relays, everything is good. Another problem that is not that many relays and this vehicle listed above W210, also it would be helpful if somebody can recommend a diagnostic tool for this car.