Hi there,
If you have clean installed the PC with deleting all the partitions then recovering your files might be a lost dream. You can use any third party recovery tool and check if you can pull out your files.
If you have updated by other means then in the PC if the server OS is working fine then try checking your Windows.old folder . If you see your files there try copying them to an USB and then either clean install the PC to your previous version or check in recovery section that if it is possible to go back to your older state of PC.
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