All right. That's the news:
I tried to reflow the GPU following this video on YT: https://www.youtube.com/watch?v=UgIEZzkGHVw
Now my notebook is able to start! In the first start some checksum indications appeared and then some confirmation for contiue with the system loading. Finally, Windows 7 starts. Great.
But, there are also bad news: I've got a problem with the FAN. It is OFF all the time! I don't know what is the cause, but my notebook now make a beep when the main power connector is plugged in. It is only one endless beep. And It seems there are no help for this case!
Any ideas?
Thanks!