Today I faced an issue I can no longer solve, while I was sleeping windows update installed an update (not sure which one, last build number I recall seeing was 9860), this in itself usually wouldn't be an issue but it seems it messed up my MBR, a rather
easy fix and so I did.
After rebooting it went through a fairly large number of steps (applying, setting up, configuring, setting up windows etc) and rebooted a fair amount of times during this, at the final step I could see it rebooted not to start again.
It does quite seem like windows decided to overwrite the bios on my Toshiba Satellite C660.
The steps I took to restore into a bootable state:
Boot into a live linux environment (partedmagic to be specific) and run smartctl on the drive, I ran both the short and extended self tests and the drive passed with 100%, I also checked the rest of the S.M.A.R.T data while at it (here's the log http://pastebin.com/tW8SqxEP )
After this I ran gparted, checked the system reserved partition on my hdd for errors (it came out clean, however ntfsresize did rewrite parts of the fs when realigning to cylinders)
At this point I rebooted and everything was fine (the booting issue was thus most likely attributable to minor filesystem corruption) and windows started the above mentioned steps of applying, setting up etc.
The steps I have taken to diagnose the issue of not booting:
record computer behavior at boot time, the power on LED turns on and instantly turns off, nothing else happens (the screen does not power on, no other LED behavior, the fans don't start and no keyboard lights turn on, the bios is set to normal boot and the expected behavior is to see the toshiba logo on screen) the first thing I did was to remove the HDD as it is not required to diagnose BIOS issues.
then I tried:
...clearing the CMOS cache
...replacing the ram sticks
...removing everything except the CMOS battery and then rebooting
...rebooting with varying combinations of battery and power cord (both of which have been verified to transmit the right amount of power, the cord with a multimeter and the battery by simply trying it in a satellite c650D)
The signs are consistent with BIOS corruption and by a rather simple process of elimination I can determine that windows 10 is the most likely cause.
to recap the events
I go to bed, during this time windows either crashed and rebooted or windows update rebooted my system
I wake up - the computer is at the bios boot menu claiming the drive has failed
I returned the computer to a bootable state
Windows did its share and died.
As for my settings the majority was at factory except for:
Made UAC a slight bit more paranoid
Made sure windows update installs all updates (recommended and required, ignoring optional as I install those based on preference (none installed at the time of writing))
Now I'm left with a tricky issue, restoring bios is not feasible due to the internal usb ports not initializing until after bios has started and aside from those I only have a VGA and Ethernet port (both of which initialize after bios, similarly the internal serial ATA ports initialize after BIOS) hence I cannot restore my computer to a usable state.
Rather obviously this did not amuse me and I am in fact quite upset about this.