Man, that's impossible if you have a video card that doesn't support pixel shader 2 !!
That is, if you have geforce 4 MX or under, you can't turn the lightning setting on !
You must have at least FX5200 or Geforce 4 Ti 4200/4600 !
Even if you have a "settings.dat" with lightning on, you will experience corrupted graphics or sth like that !
Sorry for you, bro