IPHONE 3G STUCK ON RESTORE AND UPDATE AFTER 4.2 UPDATE FAILED HALFWAY THRU

Question

I plugged my iPhone 3g in to iTunes and a new update was available for it (update version 4.2). So I downloaded it and started the update, and it got to the very last step and it quit and a pop out came saying "The iPhone "iPhone" could not be restored or updated. An error occurred (37)." And now it the iPhone won't even turn on unless its plugged in and even when it's plugged in it only shows the screen that says to plug into to iTunes, which just keeps repeating "iPhone is in recovery mode, needs to be retored to be used". And I have already done EVERY SINGLE TROUBLE SHOOTING STEPS REPEATEDLY. Nothing seems to work, if there is anyone that can help I would appreciate more than anything, this is my sisters iPhone, I was just borrowing it, now I broke it haha, I could really use someones help.
I also have an iPod Touch 2g from a year or two back that had the same problem but it was completely black no matter what, holding the home and power button or anything wouldnt work. But it still says its connected but is doing the same thing as the iPhone, it won't restore, it quits right at the end and says the same error message.

Answer 1

Your antivirus or firewall is blocking the update.
"Error 20, 21, 34, 37: These errors typically occur when security software interferes with the restore and update process. If you are using a PC, follow this article to resolve this issue."
This is from Update and restore alert messages on iPhone, iPad, iPod touch and Apple TV (2nd generation)