First post, by Sphere478
I wasn't are of the SSE switch but there are some at least in the version listed here: https://wiki.videolan.org/VLC-0-9-x_command-line_help/
Question would be though how the executable was compiled if it requires it.
Last I tested without using any switches, below were not tested on AMD:
95 SSE1 - 0.8.4b (a works as well)
ME SSE1 - 0.8.6d
ME SSE1 Kernelex - 2.2.8 (possibly newer can work but may need SSE2)
I never wanted to torture myself by trying VLC on such an old processor so haven't tried in pcem yet. Would probably be better off with Windows Media player with codecs , TCPMP....mabye potplayer but doubtful. Could possibly also have good results by compiling your own version of VLC.
For Win 98 I use 0.8.6i, not sure if it worked on Pentium mmx, I think it worked but don't remember it clearly. It needs the Unicode layer for Win98, maybe WinMe already has it. But I agree with DosFreak , Windows media player plus codecs was a common solution back then.