In message , Wolf K
writes:
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Before you do anything else, make an image of C: on a bootable disk or
USB stick first. Search for "making USB bootable windows 7" for
instructions. If the machine has an optical drive, you can make a
bootable disk. Use Macrium or similar.

Seconded, other than the image itself doesn't have to be bootable; you
just need _something_ bootable that can restore (from) an image.
(Including being able to _access_ where you _put_ the image.) I image to
an external (USB) hard disc, and Macrium 5 as the bootable restorer (and
saver - I feel happier making an image of Windows from a _not_ running
Windows); my Macrium fits on a mini-CD, and can access the external HDD.
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Good luck.
+1

Remember to make that bootable image!

Or non-bootable, but with _something_ that is.
--
J. P. Gilliver. UMRA: 1960/1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

Bread is lovely, don't get me wrong. But it's not cake. Or it's rubbish cake.
I always thought that bread needed more sugar and some icing. - Sarah Millican
(Radio Times 11-17 May 2013)