See if you can boot into Safe mode. Press F8 during boot to enter safe mode. You can also boot to the BIOS and see if there are any diagnostic tests for the HD. HP provides a BIOS test for the HD. If the HD fails then remove it and hope you can recover data. You can also use the appropriate OS Disc and choose to repair Windows.
Not even able to logon to the Safe mode as there is only a pointer flashing on the upper left corner and nothing else.