For a simple screenshoot use the built in functions Print Screen for Windows XP or what even way you do it in Vista. I am sure that Windows 7 function will be similar to Vistas.
I refuse to use Vista so I have no idea how that function works.
If you only want to get a screenshot of the actually table and not the entire screen, click on the window in question, hold down the ALT key while pushing the Print Screen button. Then paste it to Paint or what ever program you use to editing pictures and move on from there.
Someone mentioned Camtasia, but that does cost. A good product though. I am still trying to figure out a good way to compress the video because the files can get quite large. BTW, Camtasia also records audio if you want that as well.
I am going to look into BSR Screen Recorder 4. From what I can see on the web page it has a no limit free trail and records sound as well, which is something I want.
If you don't really want or need audio there are several programs that are totally free on the net that will serve your purpose.
Just type in Screen recorder freeware in your favorite search engine and you will get several to select from.