I am a software developer and I have an older coworker (60+ years old) who comes to me every time he has a question about anything involved with computers. Most of the time I am busy and I have no idea what the answer to his problem is, but no matter how many times I tell him this he winds up asking me the question two or three more times, and always comes back with more questions later.
He is also using these questions as a way to start idle conversations and I would like it to stop. How do I communicate to him that I cannot and will not help him with his problems (as it is the IT department's job) and more importantly make him understand that I believe that idle conversations are not O.K. for the workplace especially when everyone is busy?
I'd like to avoid being too direct with him as at least three other developers sit near me and all of them would hear me putting my foot down.