Hello,
Thanks for reaching out! I'm Microsoft user like you.
I can understand you are facing some issues with connecting NAS drive.
As you have re-installed Windows so you need to find user from NAS.
Please try access NAS drive console or admin page using https://<NAS drive ip>
Check NAS manufacturer vendor website for default credentials if you do not remember. then try to create a new User so that you can map NAS folder to your computer.
In case of additional questions, reach out back to me, and I will be happy to help and try our best to resolve your issue.
Best Regards,
Prakash