Ziay!

jess

What are the best anti-virus softwares that are free to download on the internet?
What are the best anti-virus softwares that are commercially available?
Is it alright to use anti-virus softwares at the same time?
What are the best things to do to prevent viruses from infecting our computers especially when we are using the internet?

KoolBluez

Free one - Avast, AVG

Else - Kaspersky

Nightowl

McAfee used to have a free version but I think it now only offers a free trial period like most reputable antivirus software/companies. Most of these companies also offer from their websites free scans of your computer without installing any software.

As for commercially available, I would stick with the well known companies that will stand behind their product and give you decent support if needed. E.G. Norton AntiVirus, McAfee Virus Scan, and CA eTrust EZ Antivirus.

I have never run multiple anti-virus packages at the same time. I suspect some combinations will work but I would be hesitate to do this as this type of software is pervasive (i.e., installing and hooking into all parts of your system) and could cause more harm than help. If this is something you're set on doing I would strongly recommend you find or get in writing from each company that makes the software that you plan on running can indeed run simultaneously.

The best things to do to prevent viruses is somewhat hard to answer without knowing things like what type of e-mail application you use, your level of experience, etc. Starting with e-mail, the most common medium for viruses, you'll have better protection from e-mail viruses when using web based applications (e.g. Yahoo, Hotmail, and just about most major ISPs) vs. applications that are installed on your computer, such as Outlook or Outlook Express. Reason being the e-mail stays on their server vs. being loaded down on your computer. They get the virus not you. Also, be very cautious about opening ANY attachment. This is mostly common sense. If you don't recognize the sender and have no idea why you're getting the e-mail in the first place, don't even open the e-mail let alone the attachment. Don't forget to also delete the e-mail from your Trash can or Deleted folder. If you know the sender but not sure why there's an attachment, once again, don't open it. If you know for a fact why you're getting the e-mail AND the attachment, then and only then would I take the next step and that's use your antivirus software to scan it before opening it.

Also be judicious about what websites you visit. Don't just click on any link from an e-mail or another website unless you know where it's going to take you. Ask yourself is it really that important (i.e., worth the risk) I go to this website? This is where a good firewall application helps out.

To wrap this up I would recommend one final thing to consider. Look at securing your entire computer and not just for viruses. Consider looking into purchasing an entire security suite from one company (vs. independent software companies) as they usually provide antivirus, firewall, anti-spam and anti-spyware software. (E.g. CA Internet Security Suite, Norton Internet Security, etc.) Pros: More for your money, better overall protection, and most important, software applications that have been tested together and proven to work together. Who needs the headache of an application corrupting another; uninstall and re-installing; hours on phone with support; etc.

HTH and good luck!