after replacing motherboard, Debian gets blank screen while booting

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http://unix.stackexchange.com – I have Debian installed on one computer. I just replaced its motherboard and CPU. And graphics card, because I use onboard one. I kept my old hard disk. Now machine boots well, grub starts well, initrd starts well and asks me for a password (because my disk is LUKS encrypted), but then about when it usually changes to framebuffer, monitor goes black and that's all. I guess the hardware is not faulty - I boot knoppix on it and it works well. I guess the problem may be that my initrd does not contain drivers for my new graphics card - can it be the problem? If so, what should I do? The last thin (HowTos)