Tell us more about your setup.
Does the computer have a DBxx serial connector, or are you using a USB-to-serial dongle (what's the adapter make and model #)?
What operating system is the computer using?
Are you using TIS2000 software, or running live on the Techline through a browser? What did you download to your desktop?
EDIT: to be clear, the computer connection isn't needed to use the Tech 2 if you're not programming modules. It works standalone to view powertrain and body data, reset codes, and run test functions.