It is Windows 7 on an HP P6000, and the problem is that the boot order does not persist across reboots. E.g.: I go into the BIOS and set to boot from hard drive, then CD/DVD drive, and it defaults the third and fourth to PXE and floppy respectively. I cannot remove or disable those, it has no option to do so that I've found.
After I save and quit, it boots normally into Windows. However, upon the next reboot it first tries PXE boot, then when that fails I am presented with a black screen saying:
Reboot and Select proper Boot device or Insert Boot Media in selected Boot device and press a key
I replaced the battery but that did not fix the problem. I cannot get the settings to save in the BIOS so that it boots from the HDD first every time.