When you say that Microsoft is preventing you to go into your boot options, that's not Microsoft. The only way to do that is either bootstrap a custom built version of BIOS onto your computer, or go into the BIOS and change the option. BIOS is roughly the firmware for your desktop/laptop, and Windows is your Operating System, they're two very different things. If anything I'd say this is HP's fault, as they _are_ the one's who made the computer so they can change the boot sequence or bootstrap their own BIOS. Where-as Windows has no control over this.
Anywho, I'd tend to agree with you. The second Steam comes out for Linux, I'm high tailin' my ass out of this Microsoft crap.