Could the system image be done just for system and program files whilst not bothering with personal files, i have all my docs/pics/vids etc backed up elsewhere, would that make it small enough for a large (32 gigabyte) usb stick?
If this is your concern, you might consider having two partitions on your hard drive: a 32GB system partition that only holds your system files and programs, and a larger partition to store your files. I don't believe the Windows built in system image backup can backup just a single partition. You might want to look into a third party program. I have succesfully used EaseUS Todo Backup Free in the past.
as for your mentions of the motherboard, is motherboard damage pretty rare? Can a virus harm this part of a computer? if the motherboard was the dead component could the new computer onto which the backup was being applied be made to believe it was the old motherboard rather than a new one(delete and forget that point if you don't want it asked on this site)?
Yes, motherboard issues are some of the least common hardware issues, at least in my experience. Only extremely rare malware created specifically for your specific motherboard could infect a motherboard. So in all reality, no. I'm not sure about the last question, but I imagine if it is possible, it's extremely difficult to accomplish and not worth the effort.
Also i see the article mentions doing it over multiple dvds, can it be done over multiple USBs instead if one usb is not big enough to hold it all.
I don't believe you can use multiple USB drives, it probably depends on the program you're using though. I would highly recommend investing in an external USB hard drive that's as large as your hard drive. I just bought a 4TB external drive for $140 a few days ago, FYI.
regarding the process of restoring from a system image, how damaged can the system be for it to work, surely some viruses could prevent booting in the recovery environment from working?
The built-in Windows system image backup can also be restored in the recovery environment on a Windows install or recovery disk, I would recommend getting/making one if you haven't already. Some third party tools have their own boot disk as well that you can use to recover the backup no matter how messed up the system is.
another question with system images is the best principle just to do one when you know the system is in good order and leave it in a safe place or to do them periodically so that newer images will contain updates rather than having to reinstall months/years worth of updates as one would if restoring from a very old system image?
There isn't really a best practice, it all depends on what result you want. If you want a definitely clean backup, just do one when you know the system is 100% clean, like after a reinstall. You could also make multiple backups instead of just one.
can you please list the types of damage to a machine which would mean that system images would no longer be enough to repair it?
Just hardware failures. You will always be able to use a bootable recovery disk (either Windows or third party) to install a recovery image. Your real concern needs to be backing up that system image properly. Storing it on a single USB stick is not a safe backup plan. If that USB stick dies, your system image backup is gone. Storing it on 2/3 USB sticks and testing them on a regular basis would be a decent backup system.
Edited by kokomodrums, 16 September 2014 - 10:11 PM.