bad cpu?

my car has been sitting for 3 years with the blown motor i get battery and finally the key i go to try to turn it over and nothing on the dash works at all but when i turn my brights on they work and my horn cuts on and stays on and the lights kinda turn on, on the cluster my friend says the cpu is gone and if its true could that keep my motor from trying to turn over? im not sellnig my car any more a guy offered me a nice price for my motor so i can now afford to fix the rx7 very fortunate im very excited

So your lights dont work on the dash but your headlights see 12V :P
Check and see if your starter is seeing 12V, and make sure the ignition signal wire is in ok shape that runs to the starter. If this still dosent work, then pull the steering columb apart, remove the ignition switch, insert a screwdriver and turn :P

Can a new CPU be purchased for the RX-7...new to this...

mazda told me NO about a new one but i have an extra one that works i stole from the JY i found out it was just my wiring harness