If the user has access to one computer on the network and it's logged in using the system admin credentials, and any sharing is going on, it's not a stretch to simply install it on the other computers.. Of course, there are other ways to remotely install a keylogger but this is one of the easiest.
As to letting friends use home computers, why not set up a special "Guest" account which has no admin rights, etc.? Of course, you son would then have to stick to only allowing friends to use the Guest account... Whenever you let folks on a computer, you're running a risk.. Be sure to run some malware scans after such uses occur..
Hope this helps.
Grif
Often my son lets his friends use one of our home computers.
My question is: if someone installed a keylogger program on a home computer, could that same keylogger program somehow jump over to the other computers in our household via the wireless router for internet - or in any other way?
I wonder about this because once when I took my computer in for servicing, I asked the technician this question and he said it was possible.
Thanks for your help.

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