This is most likely no help but will explain your problem.
Most HP systems (like some Compaq, Dell, and IBM) have special system files loaded onto the HDD in either the MBR or the start of the drive. Usually this is hardware driver or info that I would expect to see as part of the BIOS.
When reformatting the drive you are supposed to use the manufacturer's supplied utilities disk to reset partitions and make formats and to build new drives. The disk (usually supplied with the system) will identify and protect or load these special files.
If the disk is no longer available you can usually get the appropriate utilities and files from the HP web site by identifying the specific model.
There have been times when I have NOT been able to recreate these files. In those cases I got it working by taking the HDD out and using Fdisk in another machine to delete ALL partitions and create new partitions and rebuild the MBR and format the partitions setting the first to Active. Then putting the drive back in the HP/Compaq machine and loading the operating system on. This process has gotten the system working but it is not always possible to tweak the maximum performance out of it after eliminating those special files.
