Cancel button and OK button act the same

I know VERY little about vbs but was trying to do a simple script in notepad. The script is now working as it should to perform the function when the OK is pressed however the Cancel button does not Cancel, it simply sends a blank message.

the 'sent' command here works pretty much like 'net send' used to prior to windows 7

if interested you can google winsent for more info on it.

my code looks like this:

Dim inMessage
set oShell = createobject("wscript.shell")
inMessage = InputBox("Enter Message Below, then Click OK","Net Sent")
oshell.run "sent * "" "& (inMessage) &" "" "

any help appreciated

Thanks