Ubuntu update from 10.10 - TV no longer recognised as second monitor

I'm using a Toshiba laptop, which I installed Ubuntu 10.10 as a dual boot with Windows. Most things worked fine, including s-video out to a Panasonic TV.

I have updated to 11.(something, not sure which - can't find how to check! [I now see that it is 11.04 Natty]) and the s-video no longer produces a picture on the TV. [The Monitor application sees another unnamed monitor when I plug in the s-video, but it has only 30 Hz available - I think the TV is 60 Hz - and there is only the occasional flash on the TV, but no picture at all.]

(Secondary question - I also installed 11.04 onto another Toshiba A300, but couldn't get Chrome or Chromium to work properly with Flash: the download/update didn't work. [Update - I've now managed to get Flash working on Chromium - the plugin says it's for Mozilla, but later it says it works for Chromium as well. However, I couldn't install Chrome - it said i386 was the wrong architecture, but the A300 has an Intel chip. I'll see how Chromium goes])

Can anyone help: I want to use Ubuntu instead of Windows, but I find it difficult to solve problems, possibly because I know Windows better than Linux/Ubuntu. [Any advice on how to find out things about the hardware/software on the machine: e.g. which Ubuntu is installed - I see from research that it is 11.04 Natty on both of these laptops - or what the hardware of the machine is: I had to go into Windows to find out if the A300 had an Intel or AMD chip.]