1. Download greenpoison rc7 from www.greenPois0n.com
Limesn0w is not available yet.
2. Connect your iPhone 4s to computer via USB.
3. Run greenpoison rc7 for Windows.
4. Click on "make it Pois0n". entering recovery mode.
5. Hold Home and Power button together. "release power button" but keep hold home button still.
6. GreenPois0n is now in DFU mode, release home button and wait for it to finish.