Win7 corrupt file, can't boot anymore

Hello and welcome Fabio mate first please follow this
Now before we can help we do need to know what is in your machine so please do this System Info - See Your System Specs
or either enter the specs of your system in your forum profile the specs will appear when we click on that little box bottom left of the post screen it is for me the preferable option as it is easy. As you may appreciate it is very hard when you don’t know what one is working with for example a diesel or petrol engine.
(pretyped to save time)

OS Version: 6.1.7600.2.0.0.256.1

Now just where did you get the copy of Windows form because this is the very original version and it is not showing any service pack 1 (SP1) ie it should at very least read 7601 not 7600 having said that it could but obviously your copy has not has SP1 added to the OS which means the media you have got is very old indeed.

I succeed in repairing the BCD with the bootrec, it was an EFI system so some more tricky operations were needed to find right "boot" directory...
After this the machine "starts" and gives me new black screen with:

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Windows failed to start. A recent hardware or software change might be the cause. To fix the problem:
1. Insert your windows installation disc and restart your computer
2. Choose language setting then click next
3. Click “repair your computer”

File: \windows\system32\drivers\msahci.sys
status: 0xc0000098

info: windows failed to load because a critical system driver is missing or corrupt

OS Version: 6.1.7601.2.1.0.256.1
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Then I tried to boot in safe mode without success.
After booting again from ISO I went to cmd.exe and tried "sfc /scannow" which gives "Windows resource protection found corrupted files but was unable to fix some of them"
Noway to correct/replace the mshaci.sys???