My other desktop has an OEM ASUS (HP version). It has been fine and easily accepted a major CPU upgrade (from a Sempron 3200 to an Athlon 64 X2 4200). The HP version did cripple the BIOS, though. For example, there is no option to boot from USB.
I discovered that the computer can indeed boot from USB. Just put a bootable device in a USB port and hit Esc when you start the computer. This brings you to the boot menu and you can select the USB device. You will not get a USB boot option unless you have a bootable USB device plugged in. I don't know if the BIOS offers a permanent USB boot option. It certainly isn't there if a bootable USB device isn't plugged in. I didn't check to see if the bootable device shows up in BIOS if it's plugged in. Anyway, it's easy enough to boot through the boot menu.