Email checking question

Hi , New to the forum .I use Avast Free .
I recently got an email from a friend i trust . I noticed words in it that were blue , instead of black .Put the cursor over the words and Get “Shopping link added by Skimwords” . I emailed him back to tell him to look at his computer for a virus . .
What I want to know is ,at the end of the email there is an avast message to say the email was checked and free of viruses and malaware .
So if it was checked ,Why have these Skimware links got though ?
Another Question ,I run a Quick scan every week , and a full scan once a month I never come up with Any thing . I can run Superantispyware straight after the Avast scan , and get around 160 tracking cookies . Why is it Avast does not pick up these tracking cookies ?Last time i did a full scan with Superantispyware After doing a full scan on Avast .
Superantispyware found 3 programs i thought i had removed from the computer , yet Avast ,Did not . Any thoughts ?

no security programs have 100% detection…

avast (and many others) does not look for tracking cookies as they are not malware

Are cookies really spyware and are they dangerous? http://superantispyware.com/supportfaqdisplay.html?faq=26

http cookies. http://en.wikipedia.org/wiki/HTTP_cookie

you can sett your browser to block third party cookies … google it to find out how

you can clean (empty) cookie folder with programs like CCleaner. http://www.piriform.com

Superantispyware found 3 programs i thought i had removed from the computer , yet Avast ,Did not . Any thoughts ?
we need more info ..... what programs?.....detected as what by SAS ?

Hi , Thanks for the quick reply . Thing was , the email was actually 3 email all the same but all with different titles . All 3 had the Skimwords links ,all three had the same avast checked and OK message .
I previously had used Nortons ,but i got a little peeved with it with the couple of years i used it with
A the impossibility of redeeming the promised rebate .
B About a month before renewal it would get a spate of threat detections that would tell me how lucky i was that nortons was on the job ,And by the way your due to renew in X amount of days .
Then a Virus got passed it . Had a guy remove it , Following day it was back . He removed it again . And had to remove and reload Nortons to get rid of it . .I then used a Virus protection recommended by a friend . It caused problems with a forum I am on , so removed it and replaced it with Avast .
The Problem programs I removed and Avast did not find was Advanced systems care .Basicly with Super antispyware full scan , They came up straight away . All in all I am happy with Avast . I am not to Tech minded and most of this stuff goes right over the top of my head .

Advanced systems care
do you mean Advanced System Care from IObit?..... are you sure? http://download.cnet.com/Advanced-SystemCare/3000-2086_4-10407614.html

it is a legit program and not something SUperantispyware should detect?
however we dont trust IObit software here after the issue with Malwarebytes …
if you want i can give you the links to read?

Friend of mine had Advanced system care on his computer and recommended it to me .Put it on , Did the scan and it supposedly come up with all these bad things on my computer ,and get rid of them , Next time i did it ,well ,Darn if it did not find almost as many .
After a couple of months my mate started having problems with his computer .Once he got rid of Advanced system care , his problem disappeared . Not long after , I began having troubles ,I decide to remove ASC . Short story was ,it took with it the internet connection and the browser home pages … So did a restore to early time .