HD boot order changed itself?

ElkyElky

After a power cut, my computer would not boot up. My first instinct that the MBR was corrupt so I popped in the Windows 7 dvd, went to the command prompt and repaired it - as I have done in the past and has worked. It still wouldn't boot up.

I went into the bios and noticed that the hard drive boot order was different.. my Windows 7 hard drive wasn't at the top of the list and so the computer was trying to boot from a hard drive that didn't contain an operating system.

What would cause the boot order change like that?

davb

If your preferred boot order is not the default, then it could happen if the BIOS is reset to defaults (or the config gets corrupted).
I have seen BIOS resets happen before for no apparent reason, so a power cut could do it.

The other thing could be your CMOS battery being dead, if the PC is normally plugged in all the time, and then the power is removed, it would reset to defaults.

fwor

As Davb says, it could be the BIOS battery close to dying.

However, some makes of BIOS can automatically change the boot order if they can't successfully auto-detect the drive that is marked as first to boot. One of my PCs (a Shuttle) does this.