There is a new virus going around based on the CryptoLocker idea from last year. This variant is called CryptoWall. Beware!
The way it operates is it comes in via an email with a zip attachment, or a link to a zip file. The subject usually is about a shipping label, fax, invoice, payroll stub, or voicemail, among others. Inside that zip file is an executable with the virus. When you open it, nothing happens. However, after a few hours, you cannot open any of your personal files because they have been encrypted and are now being held for ransom.
To remove the offending files, a virus cleanup usually does the trick, but that is not the difficult part. The major issue is that one has to pay via bitcoins the equivalent of $500-$1000 for your files. An added awful side thing is that in an office environment, this virus also infects the server and any shared files, virtually bringing the company to a stand still. There is NO WAY to decrypt the files without the key, which they hold. So, once you are hit by this, you can either recover from a backup if you have one (We strongly recommend daily backups) or pay the ransom. By the way, acquiring bitcoins is not that easy because credit cards are not accepted.
Please, make sure to have daily backups (Let us know if you need help with this) and do not open any email attachments with zip files, or follow links to download zip files that you receive in an email, even it if seems like it came from inside your company (i.e. accounting, payroll, hr, UPS, USPS, FedEx, etc).