Problem changing a data file

[wargod2009]

Hi everyone. I am trying to change the data line (I guess that is what you call it) unit_detail=highest to unit_detail=high by going into the default cfg file using wordpad but when I go to save the change a message pops up saying: "Access to C:\Program Files\SEGA\Medieval II Total War\mods\SS6.3\default.cfg was denied." I need to change this file or else the battle maps will lag horribly due to the fact that my laptop is very outdated. Any assistance would be immensely appreciated. I am sorry if this is the wrong place to post this.

[bɑne]

First off: Use notepad to change gamefiles.
Second: Turn off your UAC, take ownership of mods\SS6.3\ or install SS6.3\ into C:\Games\SS6.3\ or similar to avoid problems.
(Yes, SS6.3 works even with Medieval II Total War still installed in C:\Program Files\SEGA\Medieval II Total War)