Are you asking whether they've got a drive mapped to the share? Check
http://www.mvps.org/access/api/api0003.htm at "The Access Web"
Or are you asking whether they've got a connection to the LAN? Check what
Randy Birch has at
http://vbnet.mvps.org/code/network/isnetworkalive.htm
(Obligatory warning: Randy's site is aimed at VB programmers. There are some
significant differences between forms in VB and in Access, so some of his
samples don't port directly to Access without making minor changes. For
example, in sub Command1_Click, there are 5 statements assigning values to
the 5 text boxes. They all use the .Text property of the text boxes. In
Access, you cannot set a text box's Text property unless the text box has
focus. Either remove the five .Text properties, or change them to .Value)
