You can send Messages thru office network Try This
step1 : start --> run --> (type) services.msc --> (press) ok
step2 : find for 'messenger' services
step3 : double click it ! change status form disabled to automatic if it is 'disabled'.
step4 : press start button & finish the process.
step5 : open your command prompt
step6 : type the following "net send ComputerNameHere some messages overhere"
