My iPhone 3G hasn't worked since 3.1 ...

Hello everyone, thanks for at least reading this post. I'm having a heck of a time trying to figure out whats going on with my iPhone 3G. I bought mine from my brother for $100 after he bought his 3GS a few weeks ago. He sold it to me without the sim card, which I don't care about because I'm only planning on using it as an iPod Touch. Well about 3 days ago, I updated the iPhone to 3.1 so that I could download some of the newer apps. As soon as I finished updating the phone, the screen showed a data cable at the bottom of the screen leading to the iTunes logo (of course telling me to connect the phone to my itunes), and the phone became locked with a slider lock which only allowed me to slide in order to make an emergency call. There was also a message that said "please insert a valid sim without a pinlock" and I also received a message in my iTunes that says the iPhone couldnt be connected properly because of a password protection. Well like I said, I don't have a sim card, nor did the iPhone even prompt me with any sort of key pad in order to enter my passcode. So I took my brothers advice and tried to perform a quick system restore. Now the message about inserting a valid sim card is gone along with the slider, but now the screen is frozen with the picture of the data cable leading to the iTunes logo. I've been able to power the phone on and off multiple times, so I know its not completely frozen. I've been able to have the device recognized in my iTunes but only as "iPhone" instead of the usual "corey's ipod", and I have also been able to start restoring the device but shortly after starting the restore process, an error occurs usually #1604 or #2002 stating that the restore process could not be completed due to one of these mysterious errors.

Ive read a few different forums and tech sites, and alot of people have had similar problems, and I have tried to follow their instructions on how they fixed it, but nothing has worked at all.

its now almost a quarter past 4 a.m. and I have been trying to research this since 8p.m. trying to find a way to fix this and I've given up hope.
If you have any advice please respond ASAP. anything will be much appreciated!

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