The Sony TV may have a non-obvious setting called "Display Area" that you can change: Go to "Settings" / Set-up / Screen settings / Display Area" and select the "Full pixel"
If you tv has no such setting you might try the settings in Ubuntu. Here's a page with some info on that: http://www.ypass.net/blog/2009/07/dvi-to-hdmi-overscan-screen-edge-cutoff-on-an-hdtv/