antivirus

There are no viruses for OS X, however there is a very small amount of malware . The e-mail you opened was a scam, something that can be ignored. In order to avoid the small amount of malware out there please do the following:

• Do not download from torrent sites.
• If you receive a pop up ad, ad, e-mail or phone call advising your computer has been compromised,these are SCAMS and must be ignored.
• Keep your OS X up-to-date by using Software Update and installing all recommended updates.

Chances are it was a Windows only virus. Can you post or link to the notice you got from the website of that company? If it was some Mac malware, you could install Sophos and run a full scan. It's free, will most likely not cause any disruptions, except for possibly very slight, hardly noticeable delays when it's active (I run it on my 10.8), and once you're finished with the scan, it can easily be removed, should you want to. It comes with an uninstaller. Sophos as well as ClamX, I believe, should be able to identify Windows viruses/malware, in addition to those designed to execute only on Macs.

You can also do a full scan with ClamXav, also free.

You should also note that no Anti Virus will be able to catch everything, especially malware that is just emerging and which hasn't yet been cataloged.

But first let's see what that company was saying.

EDIT: I'm seeing that you received the usual knee-jerk "there are no viruses for OSX." That may be true technically, at least for the time being, but the term "virus" is quite frequently meant to describe any kind of Mac malware, which does exist.

You don't have a virus. Just delete the message. Never install any so-called "anti-virus" software, as all such software is worse than useless.

i have since found this was a virus email (or so the company have stated on their web site

Everything depends on what kind of e-mail this was. If this was a phishing e-mail fraudulently trying to get some kind of personal information from you and not an attachment that you opened, then simply opening that e-mail would not have introduced any kind of infection into your computer.

So did you open an attachment from this e-mail? Until I know that, no one can say whether or not you picked up some kind of malware. It would also be helpful if you can give a screenshot (or a link to) of the whatever the company was saying about this on its site.

Sophos or ClamXav will scan your Mac for known OSX malware. I would also be highly skeptical of statements from anyone that, absent any kind of evidence or documentation, make the claim that A-V is worse than useless. Some A-V has its limited uses. In your case, if you did manage to pick up an infection of some kind from an attachment you opened, it wouldn't be a bad idea to do a full scan. That said, getting back a negative will not conclusively prove anything.