Download iBooty v2.2
Are you still having tethered jailbreak on iOS 4.3?
You can update to 4.3.1 and jailbreak using sn0wbreeze 2.5.1, jailbreak using redsn0w 0.9.6 RC12, or jailbreak using PwnageTool 4.3 instead.
iBooty v2.2 is automatically generated by sn0wbreeze jailbreak tool while it is doing its job building a custom IPSW firmware file. It should be located on desktop inside iBooty-for-4.3 folder. However, if iBooty-for-4.3 folder not found on your Desktop, you may download iBooty v2.2 here.
You will find iBooty.exe & files folder inside iBooty-for-4.3 folder. The files folder will contains ibss.4.dfu, ibss.4.payload, llb.4.dfu, notice.read, and s-irecovery.exe
Run iBooty.exe to start your tethered jailbreak device.
If you really need a guide how-to use iBooty to tethered boot your device, read How-to Use iBooty.