There various options
The CURRENTUSER function, returns the current Access user
The ENVIRON function
The windows API call documented by Dev Ashish that returns the Network lohon of the current user.
Of the 3 my preference is for the API call. Why?
Currentuser returns the userid the person logged onto this instance of Access. Its not especially secure or reliable.
ENVIRON should be the same as the API call, ie the windows userid of the person, however ive seen it spoofed so I dobt trust it.
The API call has the advantage that coupled with good network policies (one id per user, only one current logon per user and so on) you have a mechanism which can uniquely identify a user. Dev Ashish has also documented hiw to get the computername as well. If tied down with good network user policies the infomation can be good enough for legal requirements.
Have a look at the audit trail by Allen Browne and others. An aydit trail is probably over the top for what you are looking at but its probably worth reading none the less
I'd rather be riding on the Tiger 800 or the Norton