OpenCode is released in a few versions (2, 3.6, 4.0 <32 and 64bit>). Version 4.0 is recommended to be used on a Windows version like you. According to the requirements information, version 4.0 supports Windows 7 or later.
As a note, make sure that you have latest .NET Framework installed because the application strongly depends on the libraries contained in the Framework and because it has been developed using this technology.
