Apps like Camstudio, FRAPS, Camtasia to name a few. FRAPS works best for games, Camstudio I think has been dead for years, and Camtasia seems to be FRAPS but for any app.
If you choose to install it, take note the options are very in depth and are quite advanced. The right settings will record with the best quality, but also take note that due to how compressed but great looking video will be, it will require some CPU power behind it.
if you want a good recording screen with a lot built in feature .. use camtasia. a little vesion is snagit. these are not free however they are very good. otherwise just search in softpedia for some screen recorder.
HyperCam seems to be the most common among people on youtube etc although as you will notice in those videos unless you pay for it you will have "unregistered HyperCam" in the corner :eek4: not pleasent