My computer isn't booting

[Gspin]

I've just flashed a modded bios from this thread. It booted up succesfully the first time, then i changed some fan speeds and changed video shared memory to 256MB. When I rebooted, i heard the DVD drive, the HDD and the fans spinning up, but the screen remainded black with backlights off and stayed so for some time, then it rebooted and failed again. It doesn't even show the BIOS logo. Can I recover it someway?

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Solved!
I posted here because the recovery procedure (fn+esc with recovery usb stick inserted) wasn't working, but I found out I am the problem I was doing it wrong!