hi.

i supppose if it was me, i would try to impress the client by "caring" for his welfare.

a letter. something like, "we were doing routine re-evaluations of the network installed by [said company]."

heck, networks should really be evaluated every few years as the technology progresses.

"and it has come to my attention that, due to the latest advances in malicious on-line attacks, such as viruses, trojans, etc., that your present system could stand an upgrade."

on second thought, that could sound like blackmail.?

well, you get the idea.