How to view RMVB video file with windows media player classic? it says that i don't have the needed codecs or filters installed in my system?

Windows Media Player is unlikely to decode RMVB files in most common cases. Because there are multiple possibilities hiding in the encoding processes, which may be wrapped in just one RMVB file. If the codec RMVB Windows Media Player that requires is missing, you can try some other RMVB player programs such as Leawo Blu-ray Player which is a free program to use and it can play up to 4K videos.

Well try the VLC media player