[BC] PMD670 problems

[engineermike]

Hey folks,
   Anyone had a problem with one of these things not working with some computers 
AND if you can get it to connect and you copy the files to a machine when you 
delete the files from the PMD670 the files also disappear from the computer they 
were saved on.  At first I thought it was the computer having issues but it has 
happened on 2 machines now with 3 more not being able to connect to it and all 
of these machines have worked fine with this unit over the last month so 
something has suddenly changed.
Thoughts or ideas are appreciated.
Unit is about 18 months old
Same users that have always used the unit.
Mike