I flattened my pc and then reinstalled Mist it now asks me to open a "new" account. I want to reinstall my old one... how do I do it? I am currently downloading chsindata. I have my JSON files etc.
You can add/remove accounts by copying the json file directly to the geth keystore directory in C:\Users\%USER%\AppData\Roaming\Ethereum\keystore
Once done, just restart Mist and you should be able to see your account.