System name (network)

You may use the GetEnv command to retrieve any environment variable value you need.

For your question, you could use:
domain$ = GetEnv$("USERDOMAIN")
username$ = GetEnv$("USERNAME")
compname$ = GetEnv$("COMPUTERNAME")

More info at the online manual:
http://www.blitzbasic.com/bpdocs/command.php?name=GetEnv&ref=2d_cat

Did it help ?

Sergio.