Sql Server's security has nothing to do with folder access permission. It
also has nothing to do with Windows or Office reinstallation. I'd think the
user on that computer does not have corresponding SQL Server login (either
Windows integrity or SQL server login) matching his user account. You need
to know how the SQL Server security is configured (Windows Integrity
Security or SQL Server Login) and then how the user on that computer access
the database on SQL Server.