I couldn’t count the number of times I’ve warned people not to click on links in questionable emails. What’s questionable? Basically any email from a source you don’t know or didn’t request emails from.

But this morning, I fell for one in my work email account, which is typically carefully filtered. Emails with the topic line “CNN Alerts” had been appearing in my inbox since last week, with topics geared right to what I often write about. I figured my editor had signed up for the alerts. There were so many of them. One caught my eye. Click. Click again. Uh oh. Within minutes, I was kicked off my company VPN and funky things were happening. I shut down, but could not log back on.

I tell this sad story to segue into a refresher post for all of us who come across spam which could potentially download viruses and worms onto our computers and cause major trouble. First, make sure you have up-to-date virus software on your computer. And take a look at the spam settings in your email program to make sure they are set to your liking. (In Yahoo! Mail, for example, the spam settings are under "options." There, you can make sure a spam folder is set up, and you can block specific email addresses and block images from appearing in emails from unknown senders.)  But even with spam filter settings in place, know that some harmful spam will often sneak through, so you need to be aware of what it looks like so you don't click on links within them. Like I did.

If you see a suspect email and want to check it out, Snopes.com is a good web site to vet Internet hoaxes. Had I checked out the "CNN Alerts" email, I would have found that it and others with subject lines such as "CNN Daily Top 10" started appearing this month and can lead to downloading the Storm worm, malware that can wreak havoc with your PC.

Perhaps the best defense, however, remains common sense. It may elude you at times, as it did me (I can blame being relaxed after a week-long vacation, right?) But, generally, common sense should not fail you. You know whom you receive your emails from, which email lists you have signed up for, and whom you are emailing, so stay away from anything that is not from any of the above. For the record, here are some good common-sense tips from Snopes.com:

• Do not respond to unsolicited email
• Do not click on links within unsolicited email
• Be extra wary of emails containing photos as attachments. Only open attachments from known senders.
• Do not provide personal or financial information to anyone who solicits it in an email.

Common sense, yes, but it bears repeating from time to time.