Initially I was getting a message that my UserName was too long to be stored in the database. I tried increasing the size of the column in the database but this did not help. I found out, by trial and error that by using the .Substring() function on My.User.Name I could remove the computer name from the authenticated name and the program would accept this.

However when I click OK to have the new user added to the database it is not added?????
I manually added the username to the database and assigned a password and now I do not get the new user message but the password is not recognised??????

Any suggestions before I tear out what is left of my hair?

Found part of the problem.

When the login screen appears it has the truncated name in the User text box (This name is also in the POUser table). However, when the password check is carried out the program is only comparing the password with the password for the first entry in the table (this is one I put in when testing earlier) and does not find the correct entry.

If I enter the password for the first line I am given access to the program even though the users names are different. Doh!!!