It would be helpful if I knew what you mean by 'online', if you just mean logged into a network then the simplest way would be to write some code checking for the existance of a file on the file server, if the file is there you are online and if not you are not.
Create a button on a form called chek_for_online
Cut and paste the following code into the On Click procedure
Sub chek_for_online_Click()
Dim FileLen as Long, msg as Text, FileName as Text
'Assuming the file server is drive F:
FileName = "F:\somedirectory\somefilename.dat"
On Error Resume Next
Open FileName For Random As 1 Len = 1
FileLen = LOF(1)
If FileLen > 0 then
Msg = " You are online "
Close #1
Else
Msg = " Sorry! But you don't appear to be online"
Close #1 : Kill FileName
end if
Msgbox (msg)
End Sub
Hope it helps
Bruce Gregory