You know what usually helps - repair/reinstall of OS, if it does not start even in safe mode. I mean when you start from the OS CD, then press enter in the first menue (to install not repeir) and then when it detects older OS it will ask again if you wanna fix it. Then if you select this it will reinstall itself with new drivers for the hardware eliminating that no-start problem because it is actually caused by the wrong drivers. It should also save your old files/docs. ANd then just call MS for activation - guy in India - tell him old mobo burned to the ground with half of your house. You got replacement and need new activation code.