Changing from HQ to Single Store

I had two stores, one of which I have closed down. I was using HQ. All of my customers were set up as global customers. I have customers that purchased on credit and made payments in both locations. Now I want to eliminate HQ all together and just make my company a single store environment. I want to eliminate the HQ computer and second store computer. When I shut off the HQ computer, I can't check customer balances and make payments to customer accounts properly, and I can't send out statements. How can I go from an HQ to a single store environment and preserve all of the accounts receivable from all prior purchases from both locations?