Jailbreaking iPhone

[Bradleyfightingmachine]

I've tried everything! Need help, I have iPhone 4 running 4.2.1. Using windows. I've tried greenpoison and the link is down, I've tried limerain and it goes trough everything and limerain says it done. But the iPhone boots back up and no Cydia. Any help would be nice or if you have any links that would be cool too. Thanks

[iPittsburgh]

GreenPois0n download to your desktop, extract all files from the zip file, open greenpois0n, jailbreak.