apn/internet problems

[lioncat55]

/system/build.prop should mean root i am guessing sd card? most people from what i know use the andboot folder the problem is i dont have a folder called system on the root of my sd card the other peoblem is there is a step that says "Alternatively you can blow away your data.img and edit /system/build.prop" in order to use android you have to have a data.img. now if your talking about the system.ext2 file/filesystem that makes sence now the one thing i want to know is how should i get inside it from windows...or do i have to go to ubuntu? =) smarter than i seem. =P