About the only thing you haven't mentioned doing in that is to charge the device. But, with the screen flashing like that, it probably isn't the issue.
You need to try the tap-in-corners factory reset a few times. I never get it the first time. Or the fourth. I don't think the method with paper clip will work as I don't think it is reaching the point where this kicks.
I have sent a link to the image in response to the post in the image request thread. Try that. And consider a new SD card. That just about the only replaceable part in these devices and if they fail can cause symptoms like this.
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