This video will show you how to Jailbreak iOS 6.1.3 with Redsn0w Windows 8, iPhone 3GS, 4, 4S, iPod Touch.
The above video will help you Jailbreak your iPhone 3GS, 4, 4S, iPod Touch devices running 6.1.3 firmware.
In this video I was using windows 8.1 and had quite a few frustrating moments where the Jailbreak wouldn’t work. The error I was getting was exploit failed error.
All I can say is make sure you are running Redsn0w in Windows XP compatibility mode, by right clicking on Redsn0w and go into the compatibility tab.
Also try setting your CPU to affinity. All the details are in the video so if you follow it closely you should be able to Jailbreak your iOS device without any problems.
Feel free to leave some feedback if you get stuck.