New build... Windows loads but BIOS doesn't!

Hi all,

I've just returned to the proud achievement of my first PC build / first Hackintosh after 6 weeks away... and now I can't access the BIOS to get into a boot menu, Windows loads automatically and nothing else. I swear it was working fine before!

No matter which combination of DEL or F key (or all of them) I mash furiously or hold down through the boot process, I only ever get a small loading circle indicating that it's thinking about loading the BIOS, but then it just loads Windows. Is annoying.

My setup is something like this:

• Gigabyte Z170X Gaming 7
• 6700k
• Gigabyte Gtx 1060
• 32GB corsair Ram
• 512GB 960 Evo (windows 10 install, last configured as first boot)
• 240GB 850 Evo (OSx Sierra install, primarily working last I had access to it)

I did do a tiny little overclock at some stage... but I don't think this was the last time I was in the BIOS. To be honest I don't remember what the very last thing I did there was.

Is there an easy, obvious fix here? I super hope so.

Cheers,

Matt.