How to ressurect functional OS Win7 after file system crash not only recover files?

My system drive has suddenly lost it's file structure and I'm trying to find a way to get it back to life without reinstalling OS. Is it real to make this beast work again without enormous amounts of time or should I just recover all the crucial stuff and reinstall everything?

I have my bootable USB with some recovery soft, but TestDisk refuses to run after having unpacked seperately. Anyway, TestDisk is for recovering data, not the system itself, isn't it?

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