There's something you have to remember about external hard drives...

This is a slightly embarrassing story considering how much I know about computers, but I'm sure it will help out a few people.

Over the course of the night the power went out temporarily and turned my PC off. I booted it back up and heard a rattling noise from one of the case fans, which means it needed a cleaning. I crack open the case, take out the fan and clean it up. To test the fan before screwing it back into the case, I disconnect the hard drive and power the PC up with the fan plugged in. I had to do this a few times to ensure the fan wouldn't start up its rattle-fest after I put the whole box back together.

I finish up, put everything back together and boot. The boot message states GRUB is trying to load and the system halts.

GRUB, as you know, is a Linux thing and not a Windows thing - and I don't have Linux installed at all.

At this point I start to freak out a bit, because how in the hell did GRUB get on my primary hard drive? Was my primary drive borked somehow?

I run into the BIOS and check the boot order. Everything seems in check there, but then I notice something. There are two hard drives listed.

My BIOS defaulted to the external USB drive and was trying to boot from that. At one point I did have Linux on that drive and never bothered removing the boot loader.

I reset the BIOS to boot from the SATA, and ta-da, everything booted up normally after that.

What happened was that when I disconnected the SATA drive and booted a few times to test the fan, the BIOS saw the external USB drive - which was still plugged in - and set itself to boot from that since the SATA didn't exist as far as the BIOS was concerned.

Yeah, I felt pretty dopey because of that. Granted, I fixed it and everything went back to normal, but I totally forgot that you can boot from USB external drives, and when the SATA is disconnected, the BIOS will seek out the first available boot media it can find, use that and keep that setting until you manually set it back to the way it was.

Oh, and as far as removing GRUB is concerned:

There are three ways to do it concerning an external USB HDD.

1. Physically disconnect SATA HDD, boot from DOS/Win95/Win98 CD, run fdisk /mbr.
2. Physically disconnect SATA HDD, boot from Windows XP CD, launch recovery console, run fixmbr.
3. Use Partition Wizard. The home version is free, and allows you to get rid of a GRUB boot loader from an external USB HDD without having to do any extra crapola. Works quite nicely.

Published 2010 Jun 8