If there is no spark to the plugs, you may have inadvertently blown a fuse for the ignition system when changing other parts. Check the fuses in the box under the dash or under the bonnet. Also have a look and make sure the little carbon brush pickup hasn't fallen out of the distributor cap. Its the little black thing in the middle inside of the cap. It is spring loaded and sometimes can fall out.
I can help you but I do need the actual code. For an example (P0420 Catalyst Efficiency Problem). Also make sure that all wire connectors are fully seated. Hope This Helps.
None of the main fuses have power ? Do the headlights and interior lights work ?Do you have power from the battery cable to the box ? Could it be a problem with the key switch ?