"Code Purple"

What in the world was “Error Code Purple,” . A quick search on the net revealed that this was a booby trap placed in HP and Compaq computers in which a “tattoo” or numerical signature of the motherboard and hardware configuration is created at the factory and encoded into the restore disks on a particular computer. When you re-install your system, it checks to make sure the system has not been modified. (new motherobard) If you have modified your system, the “tattoo” generated by the checking program will be different than the original, and the system will not boot.

fix;
Boot from a live cd or recovery cd like miniPE (or hook your hard drive to another computer) just rename the c:\hp folder to something else. Reboot and finish installation.