Remote Assistance

I am sending a new post as I felt the last thread was no longer be read.

Recap: I would like to try and use remote assistance to help, in a small
way, a friend with continuos basic problems.

I have downloaded TeamViewer which looks perfect for what I want to try and
do.

Is there any possibility of infecting either PC if there is an unknown virus
lurking on one of them?

Also I tried emailing this programme but my anti virus didn't like the look
of it, probably because of the type of programme it is ???

TIA

B.W.