Dash, you are correct in the respect that an Unpatched version of SFC 1 will work on XP.. try patching to 1.021 or to 1.03.. then you will see SFC 1 dies not work on XP without using the SFC 1 fix file... as for SFC 1, I much rather play with the game patched with the fixes than to play unpatched.. but that is me..
anyhow.. just some more FYI.. i believe it is the way XP recognizes the SFC CD vs the game patch...