My computer is protected with a firewall and antivirus software and all my counselling work (emails, transcripts of ‘live’ sessions etc) is kept in a password-protected folder. I would recommend that you also make sure your computer is adequately firewalled and installed with current antivirus software.
I recommend that you use hushmail which is a private, secure free email service that is encrypted and has an inbuilt virus and spam scanner. Hushmail is free for personal use and for extra security you can store our counselling emails on the secure Hushmail server rather than on your computer.
I use Skype for ‘live’ text sessions as it encrypts messages so they cannot be read if they are intercepted by a third party. Skype also allows us to use webcam facilities, if you wish.