Getting the Source Drive Mac is run from?

[LetsRideBaby]

str s.getwinexe(win() 1)
out s

Thanks for the help but that just give me this
C:\Windows\explorer.exe
im looking more for just the drive letter it is run from or the folder maybe.
or a way to set a working folder for it to look in to..

test\test.exe when this runnings on a usb drive i need to find a text file that would be in the folder above the test.exe like
test.txt
or
test text files here\test.txt

now i need to get to that file when this is run from a usb drive or any drive like cd or dvd.