If your stuck on 20% on the new TaiG jailbreak make sure to follow this guide.
Navigate to Control Panel > System and Security > System and check the System type of the version of Windows install on your computer.
If your operating a 32-bit System, you need to download 32-bit iTunes 12.0.1 from here.
And if you are running 64-bit version then download a 64-bit version of iTunes 12.0.1 from here for 64-bit Windows.
Now you can continue to use our guide to jailbreak.