Well until someone official comes along, which may be a while as it's a holiday in the US/Canada right now, I'll try to answer you,
Firstly you should know that NO antivirus, no matter what brand, will protect you against everything out there. It will protect you against millions of different kinds of viruses, trojans and malware, but you have to exercise due caution when surfing, downloading, file-sharing etc. It is also vitally important that you keep your operating system, all parts of it whether used or not, totally up to date. The latter goes for your software too and for the firmware, if any, that your hardware may use.
Also different products will often detect things that another has missed and vice versa. But warning: NEVER run two antivirus applications at the same time. One antivirus plus one or two or three anti-spy/malware applications is fine though. Also make sure you have a good firewall, which McAfee includes. If you use a router, it should also have one.
It's wise to have extra tools on hand and updated ready for any emergencies. I have SpywareBlaster installed which guards in the background silently, plus I keep a copy of Malwarebytes Free always updated and ready to go, just in case.
There are a few mentioned HERE, scroll down to "3rd Party Tools". Exterminate-It is a specialized tool for specific kinds of infections, as per their website, and as it isn't free if you want full functionality, I haven't included it in that list, it also includes an antivirus engine and may clash with McAfee VirusScan as a result.
One of the developers of Malwarebytes put it very well how his particular tool works alongside antivirus applications and the same goes for many others I am sure:
A quote from one of the lead developers of MalwareBytes (Bruce Harrison) :
As far as why MBAM is very good at dealing with this infection, that is simple. MBAM is designed to be very good at dealing with malware that the AVs seem to be having problems with. I do not spend my time making MBAM detect millions of infections that any decent AV already detects as MBAM is DESIGNED to work alongside antivirus software, not replace it. A huge chunk of the research that goes into MBAM revolves around what we see making it into HJT threads as the vast majority of these threads involve antivirus software that was in some way bypassed.
Lets settle this now and avoid any further misinformation. MBAM is now a very good backup to any antivirus software and will only get better in the future. MBAM will NEVER add antivirus abilities to its core app and is always advised to be used WITH antivirus software. We actually get this question a lot in the forums and I assure you that we always say :
"No, MBAM can't replace your existing antivirus software and is not designed to."
A good first defense against bad links on the Internet is McAfee SiteAdvisor which is a free download and is included in some packages as SiteAdvisor Live. Another, which can be used at the same time, is WOT. Both are designed to warn you that certain links, web pages etc. are dangerous.
Peter - Thanks for the advice and pointing me to Malwarebytes and Spywareblaster.
I thought I have always been careful - but evidently not enough! I downloaded Malwarebytes on three of my computers and did a quick scan - one was infected and the other two are clean. I naively thought McAfee would solve all threats and now know differently. I will be more vigilant in the future.
Thanks again for your reply - holiday and all!
Secunia is also a great tool to have.Alot of people get infected as Peter said through outdated programs that are not patched.Secunia PSI is a free program.When run will give you a full view of any missing patches or updates for all of your programs.Here is the link.
http://secunia.com/vulnerability_scanning/personal/ After scan it will tell you of available updates & show a complete run down on all updates ibcluding microsoft.
By the way, in my post above referring to being OK to have 1, 2 or 3 anti-malware programs, I meant those without real-time scanning components as those could feasibly clash with Virusscan. Sorry if I mislead anyone.
The only exception I have found is SpywareBlaster which works slightly differently from others as it simply lurks in the background not actually scanning anything.