With Freescan, read your radio, then CTRL K, then auto select. You should see one with a check mark. If so send this back to the radio. If you didn't see 1 checked, highlight the system that you want asigned to 1. It is BLUE now. Then on the right, you see find free, 1 should show upo, or you can assign 1 in the quick key block. now ctrl k again, auto select, then send this back to the radio.
I had the same problem before and Upman helped me. It is tricky to "re-enable" SO 1 if you have turned it off. You may have to ask for a step by step fix to the problem. I think it involves holding a certain button while turning the scanner back on. Not sure, but as I said Upman did help me before. It is posted on RR somewhere.