DM500HD no start/boot

Hi

My brother's original DM500HD was discontinued without being shut down properly.
Since then it has not been able to start again.
When the power is switched on the LED is red and there is den.Ved pressure "Merely switching" flashes to green and returns to red.
It can not be contacted on the network and will have no IP router.
I can not contact it with the USB cable, but DreamUp and Optiflash get contact but then there will be no more.

Where do I start?

I certainly thought it could be the one that was the problem, but even though I've read some here and made many other boxes to work, I can not figure it out with bootloader and in what order to do it?

#1 First flash the bootloader, then put new image on?

#2 But again, can not figure out the bootloader manual?

When I start DreamUp I get often told, can not find com ports, aborting.
By DM500HD I use a USB port, with clones a USB to Serial converter, it is often better.

#3 Is there someone who has a solution to the USB problem also?

Now I have downloaded the latest version of OptiFlash, and hope a kind soul will link to a boot loader for an original DM500HD I can not clean out what it is for, I efforts shall try.

I try to donate to get a key and full version, but in the end I end up on a website with no progress.