I'm not sure if you can change it from packets to megabytes. A packet is information which has been formatted for transport (see following link for further information). I know that when I had a dial-up internet connection (with an external usb 56k modem) it would tell me how much in megabytes, but now that I have adsl broadband, I connect to a Netgear adsl modem through the ethernet port, which tells me how many packets sent and received, because it's a different means of sending information. Also, the pic of two computers shows that your computer is connected: Depending on the specifications of your computer, you could have a few of these, and/or wireless as well, etc... http://en.wikipedia.org/wiki/Packet
Is this what you meant? Did you recently change your type of connection?