e mail virus protection?

[DunbarPappy®ϟϟ]

When using a browser to view mail, like here @ Yahoo, some rules to follow:
Don't open attachments (even from someone you know) unless you were expecting something specific.
Like you, your friends may have been compromised and their mail is forwarding malicious content to their contacts.
Use a browser that is 'locked down' to curb hidden scripts that are a big reason PC's get infected.
I highly recommend Firefox, with these mod's:
FIREFOX: Tools> Options> Privacy> top drop slot set to "Firefox will use custom settings..."> Check 'Accept Cookies from sites'
â–ºUn-Check 'Accept 3rd Party cookies'.

A good collection of effective security & privacy add-on's (Official Mozilla) is here:
https://addons.mozilla.org/collections/d...nbarpappy/
"AdBlock Plus" (with 'subscription' added) helps defray rubbish.
►► At minimum, get the #1 item for malware prevention: "NoScript", which constrains automagically fetching & deployment of potentially tainted assets, and offsets the Microsoft install if it's rubbish.
Bookmark and refer to this page for how it works, and how to use it when sites don't function as you need: http://noscript.net/features#contentblocking

It's really a matter of keeping your PC clean at all stages that makes you more safe, but especially browsing habits.

INTERNET EXPLORER does not control returning assets very well no matter what settings you have (or anything else) and won't give nearly the control as Firefox or Chrome*.
It is junk.
Use at your own risk.
*Chrome has it's own privacy & advertising issues.