OpenWindows was probably started in the background (using the "&"). Exit OpenWindows, and run the command in foreground: /usr/openwin/bin/openwin
If this does not help, then perhaps some daemon or process is "holding" the console. Type the command: fuser /dev/console.
A list of process IDs is returned. Examine these processes to determine if an application has hold of the console (using the ps(1) command helps).