I have said this recently and it’s worth saying again — so long as you have an up to date version of Windows, with the monthly security patches — Windows is a pretty safe operating system. Sometimes, it’s the things we add to Windows that make it unsafe. You know the names of some of those helper programs by now and you know to keep them updated (or remove them) if you use them — Adobe Flash, Adobe Reader, and Java.

However, I want to share with you the biggest cause of malware (formerly known as viruses). It’s YOU. Yes, that’s right — good old user error.

People click on things that they are not supposed to. You open attachments to e-mail that you have no business opening. You click on ads. Your kids run free games. You install some unproven piece of trial software. It happens to the best of us.

Specifically, I want to tell you about a nasty piece of malware called CRYPTOLOCKER that has been sweeping the world since September. It comes into your e-mail as a .exe file (dot exe file). EXE in Windows means executable. This means its a program, much like Microsoft Word or other applications. Cryptolocker is particularly nasty. It encrypts your entire hard drive. That means you are locked out. The proponents of cryptolocker give you 3 days to pay them $100 or more to decrypt (unlock your data). And they really follow through on that…..

Fortunately, I haven’t faced this situation with one of my clients YET. If you weren’t the type that stored anything on their computer of value or had data backed up elsewhere — I would just say — let’s erase and start over. On the flip side, if you were locked out of important files that were not backed up…..I would propose that we buy a prepaid credit card from CVS or WalMart….. get your data unlocked and then transfer it off your computer, wipe it and reinstall Windows. With the prepaid credit card you can be sure that the bad guys can’t hit you up for any more damage.

This ugly scenario can all be avoided. Don’t open attached files to e-mail that you are unsure of. Use an e-mail service or program that provides basic scanning. Never ever open an EXE file attached to an e-mail. Those types of files have no business being attached to a message.

Many of you have an external hard drive attached to your computer. That’s a great first step. However, if you have files that you just can’t afford to lose – a local backup is not enough. Please invest in an online backup service that will back up all your files — AUTOMATICALLY.

My best picks for this service are Carbonite.com, CrashPlan.com, or iDrive.com. Plans start at about $60 per year. Multi-computer or family plans are available too.