Note: In order to prevent computer viruses from spreading, e-mail programs may block sending and receiving of certain types of files as attachements. You should check from the security settings of your e-mail program how attachments should be handled.
Meaning of this traslation is wrong. I would translate it like below:
"To prevent of computer viruses e-mail programs can prevent sending and receiving of certain types of files as attachements. You can check from security settings how attachments should be handled.
First sentence has wrong subject, not the viruses prevent.... it is the e-mail programmes that prevent
(annoying that I have to write my comment before seeing that somebody has already written the same thing - I should learn to check it first....)
My version of explanations:
In order to prevent computer viruses spreading, e-mail programs may block/hinder sending.... You should check from the security settings of your e-mail program, how....