changing .js files

[eagle00789]

I know, the topic title is a bit wierd in this forum, but:

I just changed all mu batchfiles so that i use only .js-files and XPlode. The problem i have now, is this: I run all the installations from the cd, but to succesfull run a few installations, i made a .js wrapper around it. these .js-files run the actual installer. in those .js files are still paths to %systemroot%. what variabele do i have to use, so that it will look in the correct folder on the cd.