Tech question: Laptop to HDTV - How the heck do I switch off overscan?

I have a fairly new laptop with HDMI out which I was hoping to plug into my HDTVs. I have two different models - a Wharfedale which I wanted to use as a large monitor on my desk, and a larger Sony in the living room. When I plug my laptop in via HDMI the picture looks great, but I'm missing a good chunk of picture information (it appears zoomed in, with all edges being cut off). I've tried changing the aspect settings on the laptop with no better results. Most online guides I've sought suggest it's a setting on the TVs themselves, but I can't find any options to switch off overscan on either set. Surely this should be a simple thing to fix? Any other ilxors had this problem and know how to fix it?

that sounds more like zoom mode on a TV? (is zoom mode same thing as overscan?)
on sony's there's usually a picture mode (wide, wide zoom, zoom, etc...) it might be called p.mode on the remote.

I don't think it's the zoom (besides there's no zoom option on either of these TVs). I think overscan is slightly different and quite common, I just can't get it to switch off.

there's some vague tips on the internet about accessing 'full pixel mode' via a menu option, but i'm surprised at least the sony tv doesn't have a zoom/wide zoom/wide/normal feature. that seemed to be standard.