Problem jailbreaking iPhone 3g with redsn0w and greenpois0n (Was previously jailbroke

[TalishHF]

I am having trouble jailbreaking my iPhone 3G.

Redsn0w issues:

• I am running as admin (Windows 7)
  
• I am running in compatibility mode
  
• Redsn0w recognizes DFU mode
  
• When I have Install Cydia checkbox checked, I click jailbreak and the program closes
  
• When I don't have Install Cydia checked it jailbreakes the phone but freezes on boot screen on re-boot
  

Greenpois0n issues:

• I am running as admin (Windows 7)
  
• I am running in compatibility mode
  
• Greenpois0n does not recognize DFU mode
  

iPhone details:

• iPhone 3G
  
• Firmware 4.2.1 (Cannot update to 5.0 on iPhone 3G only supported on 3GS and up)
  
• Modem firmware 5.15.04
  
• Model MB489B
  

[D3xus]

Do you have the driver software for DFU mode on your current computer? If not, follow the steps to get the phone into DFU and confirm that you can see a message appear that Installs the driver software for DFU mode.

[TalishHF]

Do you have the driver software for DFU mode on your current computer? If not, follow the steps to get the phone into DFU and confirm that you can see a message appear that Installs the driver software for DFU mode.

When I follow the steps to enter DFU mode it works in redsn0w and recognizes the DFU mode but no message comes up to install drivers, in greenpois0n it just doesnt recognize DFU mode it doesn't say anything about jailbreaking, I have previously jailbroke with same computer and I haven't removed any drivers or iTunes or anything so I don't think that is the problem.

[D3xus]

What is the version of iTunes on the computer in question?

[TalishHF]

What is the version of iTunes on the computer in question?

I'm not sure I'm not at the computer now I'm at work, but I updated it even after i couldn't jailbreak, still no luck. I think it's really wierd how it was previously jailbroken.

[D3xus]

You shouldn't be having a problem with it... downgrade the iTunes to 10.4 and try DFU mode again.

[TalishHF]

You shouldn't be having a problem with it... downgrade the iTunes to 10.4 and try DFU mode again.

How can I downgrade iTunes?

[Modestep]

How can I downgrade iTunes?

Delete it from your computer (uninstall), and then install the version you want.

[Grin]

Delete it from your computer (uninstall), and then install the version you want.

Absolutely not.
Apple has shells that can't be removed.
You need to search for the .dll to kill it.
It prevents downgrade.
Dont believe me try it.
It will say this version cannot run because its build is based off of a newer version of iTune.