Iphone in apple logo loop not going to dfu mode?

Hi, my iphone 3gs is stuck in a loop of an apple logo, and it can't be taken out of a power source or it dies. I have tried to put it in DFU mode in various apps such as redsn0w and tiny umbrella and recboot. Please help me. Also when i hold down the power+home button to turn off, the apple logo come back in 3 seconds. It is jailbreaked and on ios 5. I have tried everything please help me. Itunes does not recognize it.

Your phone is bricked. Hook it up to iTunes and reset it