If your battery cables and ground check out, keep moving along - check for fuel and spark.
If you used a pressure washer on the engine, take a few moments to pull your plugs - it's very possible that you may have had some water get down into one (or more) of the spark plugs. Did you cover up your coil packs as well (where your spark plug wires plug into opposite of the plugs)?
Many modular cobra owners who use a high pressure washer (or garden hose on full blast) to clean their engines learn that using a high blast of water can create problems with the spark plugs and/or electrical connections under the hood...
