device completely dead, no matter what I do.
The phone started to shut down once in a while and there were trouble wakeing it up. Things got worse and after about two weeks the wake+home way seemed the only way to bring it back to live once in a while, thereafter it went completely dark.
I thought its the battery and replaced it. However, still the same thing, there is no way to make it show any sign of live. Same story when I hook it up to the charger - all remains dark.
What else can I do? What's the most likely issue?
Id try a restore or dfu before opening. I've had issues with the latest ios 4.1.x causing intermittant crashing similar to your description on 2 phones. It has resolved after I dfu'd/restored . Sometimes I thought the phone was dead, left the phone overnight, and it turned on no trouble in the morning. Bear with it, it may not fix first or second go but it will . I occassionally still get a freeze but this is rare