Unhook your negative battery cable for about an hour. When you hook it back up, the computer should reset itself. Make sure your key is in the ignition.
If not, there is a resetting sequence in your owner's manual that tells you how to mate the key to the ignition. Follow the instructions PRECISELY! You'll need an analog watch for timing the procedure, as it deals with seconds.
ignition switch
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Are you using an original key, or a replacement that has the proper security computer chip located in the fat plastic part of the key? If not, the car's security system will keep the ignition locked and will not allow you to turn the ignition switch. ALSO: some earlier models of Focus had ignition switches that were a problem. If you ARE using the correct key and can't turn the switch to start the car anymore, the ignition switch may have to be replaced.
Very good.
http://www.ehow.com/how_4509339_replace-ignition-coil-pack-ford.html
Insert key, use a something thin to push on the release pin which is on the bottom of the ignition, while pushing on the pin turn the key until the pin actually pushes all the way in, pull the ignition out using the key.
Program a new key and ignition to a 2000 ford focus
Is it an "after-market" radio? It sounds like it was wired to a "hot" terminal that is not controlled by the ignition switch.
Usually, replace the spark plugs and/or the #2 ignition coil.
Actually , there isn't a distributor , it has a Coil On Plug ( C.O.P. ) ignition system
Ford uses a distributorless ignition system or D.I.S. It does not have a distributor. it has a coil pack.
I would have the ignition itself replaced. These go out all the time and will leave you stranded. Get a new ignition keyed to your current key and you won't have to do programming. A locksmith can do this for you. Do it soon though before it stops turning.