At least once per ninety days, I have at least one client who gets the ORA-12541 Error Message while using Banner Navigation on a Windows PC. This usually happens because the client did not remember to heed my warning to disable auto updates as it will unfortunately overwrite their needed jvm.dll files.
A temporary fix is to locate the jvm.dll files in the Oracle folder and correct them to the necessary version that supports the Banner Navigation. Be warned that update will eventually overwrite the files and you will have to make another trip to fix the issue which will upset a paying client.
To correct the issue permanently, first disable auto updates for Java. I would also disable automatic Windows updates as well as these work in the background and often slows the Windows PC process and Internet connection. Once auto updates on Java are disabled on the computer, locate the jvm.dll files (801 KB, 2880 KB, etc) in the Oracle folder and correct them to the necessary version and size that supports your Banner Navigation.
Be sure to restart the computer or you may end up getting an FRM-41214 Error Message when you try to launch Banner Navigation once more.