I've been seeing a similar issue on a DELL XPS 13" Developer edition I got back in June -- ran fine with ubuntu as shipped with Dell, and then I wiped and installed OpenBSD and now can't even access the BIOS.
I'm *sure* it's a BIOS issue as the BIOS is probably trying to do something silly with the hardisk. Haven't gotten around to flashing the BIOS to a newer version as I'm fairly sure I'll need to remove the harddisk before the system will even let me boot (and that involves taking apart most of the laptop). It's sad that BIOSes are so buggy these days, and a bit crazy that something you do to the disk would cause the BIOS to freak out. Oh well, whenever the Dell support people pick up the phone, I'll complain to them for all the good it will do. The Dell had no problem booting the install media from usb, was just when it came time to try and boot from HD that the BIOS freaked, and now won't allow me to access the BIOS settings or the "choose which media to boot from" menu. To the OP -- This is definitely not OpenBSD breaking your system, it's OpenBSD doing one of the things it does best... exposing bugs in *other* places (: and I feel your pain, it's quite frustrating when hardware we've paid for can't handle something that should be easy. gabe.
