BigFish Games is just a client which downloads the games you bought or just tried using trial mode and there is no way it can lock up a PC. From what I understand, it seems there are leftover registry files: when you removed them, those keys were left as they were preventing you from installing the client again. For this to happen, you should install Wise Registry Cleaner Free and perform a scan for registry errors or leftover. Only then you could try and reinstall the client. You will see that the setup package should work as it has to work. Also please note that the client connects to the Internet to download necessary setup files and libraries. It is most likely possible that something is blocking the communication between the client and the servers. In this case you should temporary disable any security tools installer or simply disable Windows Firewall.
