An Atom Bomb to Kill a Gnat E-mail

We recently received this (edited) e-mail from a Client, which we feel could be of interest to other users:

The error message read: Service Executable has encountered a problem and needs to close.  We are sorry for the inconvenience.

Our Client said this: I sent the above message to you because I thought - erroneously I might add - that it was caused by my changing some settings on my computer in order to view my site before letting it go live. This was pure coincidence. That said, I am passing on what new info I've gleaned, in the hope that you will have the answer if someone else asks.

I believe the problem is caused by having Windows Defender on one's computer, as well as more than one other spyware program. I have a few. I tend to use an atom bomb to kill a gnat. I need to know that gnat is dead. And I have this bulldog mentality that prohibits me from going forward, because I need to first understand and fix problems as they come my way.

Anyway ... I pass it on. Hope it elucidates if nothing else.