The specified report only shows the 50 most recent logons for the selected user. To find all computers a user logged into, you should use the report below. Replace "YourUser" with the user you want to report on.
Also note that user logon info is purged periodically based on your Scanning & Cleanup Options. These settings can be found in the Lansweeper configuration console under Scanning Servers\Your Server\Options.
Select Distinct tblCPlogoninfo.Username, tblComputers.Computername,
tblComputers.ComputerUnique
From tblComputers Inner Join
tblCPlogoninfo On tblComputers.Computername = tblCPlogoninfo.Computername
Where tblCPlogoninfo.Username = 'YourUser'
Order By tblComputers.ComputerUnique