Bricked XPS 15Z

Hi,
It seems that I bricked my XPS 15Z.
I started a week ago with flashing the BIOS to the version in this thread page 1, all worked well

Later I found in this forum BIOS versions A12 pre-configured and tested by some people with different settings (volt modding etc...) . I flashed 2 more times, first time went well but the second time didn't go well.

Black screen, high winding fan, CAPS lock light on, .... bricked

No immediate panic as a lot of information can be found here and in other forums, however after trying 2 days several things, I must admit I'm running out of options.

so far I tried following things :

- created a usb stick with mini dos version and a clean BIOS copied on to it. -but it won't boot from that and I believe no USB ports are detected on boot, as the usb stick has lights but none light up.
- created a bootable cd with ISO but it seems it won't boot from that either.

Let's hope it's my mistake but can someone confirm the procedure that I'm using is correct?

- Power off laptop, disconnected the battery
- Unplug laptop
- Press Right Arrow Key and keep it pressed
- Insert Power cable
- release Right Arrow Key

The above just won't power up my machine. So I have a few questions.

- is the "Right Arrow" key the correct button to use on the XPS 15Z or is there another key combination? If so what is the magic combination.
- do I have to try the above procedure with the battery connected or disconnected?
- Is there a difference between US XPS15Z and European?

Any help is welcome.

Thanks,

stoffg