you should be able to set your boot device from inside the bios, no boot menu (f9) is necessary. also make sure legacy usb support is enabled in your bios or your mobo might not always recognize input key commands from a usb keyboard
P95 only confirms that you are making no calculation errors, for games and entertainment this is no setback.
If you use the system for work or scientific calculations its a big problem since you might be resulting in incorrect solutions