Hi everyone!

I have an iPhone 3G that was on 3.1.3. I previously had it jailbroken (3.1.2) but then I didn't jailbreak it after upgrading to 3.1.3. Anyway, it started acting up on me yesterday, just shutting off and coming back on randomly. When I got home I googled this and most people suggested restoring my phone. When I tried to restore, while it was synching, the phone would shut off and on, like it did before, so I obviously wasn't able to restore that way. People suggested going into restore mode, and DFU mode. I have tried both, and during the restore, after the status bar under the apple appears on the iphone, the phone just restarts, thus ruining the restore. Now my problem is, not only can I NOT restore, but I also cannot get out of the recovery/restore mode! I have tried iRecovery - none of the commands work other than 'reboot'
I have tried iReb, snowbreeze, all with no luck ... snowbreeze seems to install the firmware, but then the screen stays at "downloading firmware" for a long time, and then the phone restarts.. I really don't know what's wrong with my phone, and it's very frustrating! Any help is GREATLY appreciated!

Thanks!