Several times I am asked for assistance to repair the computer that is malfunctioning and shows various errors. What I can do from here is to recommend general solutions that solve most Windows problems.
In particular, one of the most frequent errors is that of Windows which warns the user of a missing or corrupt file .
Perhaps due to the effect of a virus, perhaps due to a bad use of the cleaning programs or for some manual error, the error " file not found or corrupt " (file not found) concerning a .dll file can occur. exe or .sys or in any case a system file for which Windows does not work because that file it needs has been corrupted and deleted.
In Windows 7, Windows 10, Windows 8, Vista and even XP there is a command to use when Windows is not working well that does the checking of system files.
It is not a graphical tool found in the start menu but a command to be started at the command line from the dos prompt.
The tool is called System File Checker (SFC) which scans the files on the computer, compares them with the original ones of Windows 7 or XP and if it finds differences, missing or corrupt files on the PC, copies the original of the file by overwriting the corrupt file .
To work the System File checker it takes a copy of the installation disk of the same Windows that is installed on the computer (download the Windows 7 installation disk in Italian if it has been lost)
The files are then replaced with the original ones without the need to reinstall or restore Windows.
To run System File Checker you must go to the Start menu, write cmd in the search box, find the command prompt (it is also in Programs - accessories ) and open it by pressing the right button and choosing the Run as administrator option.
With the Windows installation disc inserted in the drive, type the SFC / SCANNOW command and press Enter.
The system file check therefore requires you to insert the installation CD every time an error is found.
Correction of corrupt or missing files will then be automatic and at the end you can be sure that the error of the file not found does not depend on Windows.
More options for using SFC are explained in a Microsoft help article.
You can also use the SFC / Scannow utility from the Windows Fix Win problem solving program if you get stuck from the command line.
If the SFC command doesn't work in Windows 10, 8.1 and 8, you need to fix the scan utility with the DISM command.
Specifically, open a command prompt window and type:
DISM / Online / Cleanup-Image / RestoreHealth .
If the DISM command hasn't changed anything, restart your computer and run the SFC command again which should now be able to replace the damaged files with the correct ones.
If an error occurs again, the only other solution is to check the files that are started with the computer, those present in the boot sectors that can be verified with programs such as Autoruns that control automatic startup.
After running SFC / Scannow, if problems are found, you can use the SFCFix tool to correct them.
A problem could arise after installing a service pack many of the Windows files are replaced so the original ones on the installation disk are not updated and are not good.
If the system file check (SFC) compares the post service pack files inside the computer with the older ones on the installation CD, it will not be able to restore the corrupt or missing files.
So you need a handy installation disc that includes the latest updates with the latest integrated service pack: for Windows XP the Service Pack 3 while for Windows 7 the service pack 1.
You can also use an ISO image of the installation disk mounted on a virtual CD.
Experts can create a customized installation CD with AIK.
In summary, when Windows is not working and to resolve the error of files not found or corrupt, first try a system restore, then try SFC / SCANNOW or use the restore option by starting the computer from the installation CD.
If everything goes wrong, If Windows does not start and does not start, reinstall Windows 7 without losing anything.
