There have many articles on problems booting a Windows machine with Linux as a dual-boot and some with Linux as only OS. Although many answers have been given, most only work under special circumstances, and vary by motherboard MFG.
The problem is with the newer Firmware within the Bios Boot console. I had an HP 400-224 PC with Windows Pre-installed. After trying many Tips and Tricks, I stumbled upon an answer that worked for me and its easy !!!
This is how to get GRUB 2 to come up at each reboot on any store bought Windows machine dual-boot, or standalone with Linux.
1. Download newest version .ISO of UBUNTU Live LTS or MINT Live LTS to your desktop.
2. Burn .ISO to a DVD using a good burning program that verifies success.
3. Load the Live cd onto your desktop (of course, change boot order in Bios to boot from CD first).
4. Install the Live Linux onto a USB stick (8gb or above). DO NOT change any partitions, just select erase entire drive and let install program complete. Remove CD
5. Reboot and go into Bios. Disable SecureBoot and FastBoot. Make sure both UEFI and Legacy are open and boot order for each is CD, USB, HDD. Remove any instance of Linux in the boot orders. Save settings and exit. Grub 2 will come up and give you all options for booting including BOOT FROM HDD).
6. Make sure it will boot to your USB, then go back into BIOS and change boot order of UEFI to boot from HDD.
7. YOU ARE DONE !!! and now have linux on a bootable Flash Drive and HDD !!!!