RGB To S-video Converter For Using HDTV As Computer Monitor?

A pal of mine with low sales resistance went out and against advice,bought a Wal-Mart special; an HP Pavilion "Slimline" with No S-video and HDMI outputs. According to the specifications for this HP S3713W, the video/graphics are all on the motherboard .

http://h10025.www1.hp.com/ewfrf/wc/document?docname=c01623239&lc=en&dlc=en&cc=us&lang=en&product=3870526

Furthermore, though there is in her "Slimline" one available slot provided to accept a "replacement" graphics card (for whichever model would have such a card) according to the manual, it will accept only "low profile" cards, and even at that they warn it still might not fit, so as to allow the inputs and outputs be exposed at the opening.
And since for her computer, this would not be a card replacement,those "cables" and plugs they refer to would be who-knows-where on the motherboard, or even hard-wired to it.

So now I'm wondering about something like this RGB to S-video
converter . . .

http://www.js-technology.com/product_info.php?products_id=34

My friend is largely blind, but she can see images and text on a large screen. My question is this: would such a converter enable video output from her computer to a large 42" LCD HDTV--and if so, would the mouse function be operative on that large screen same as on the 19" LCD monitor that came with her computer? Most importantly, would she get a full 42" display of her desktop and applications?