I'm using opensource driver there is an overscan, my hdtv/monitor res.1920x1080 24" how can I configure the screen, if need more details let me know (edges of the picture are lost ubuntu 14.04 LTS nvidia gtx550ti graphic card
Overscan is a function of the monitor - you should be turning this off on the monitor, not on the PC.
Graphics drivers do sometimes have facilities to correct for overscan in the monitor but these are intended only for monitors where it's impossible to disable overscan, which is basically CRT monitors. On digital flat panels (LCD etc) you will get a much poorer (blurry) display quality if you do this because the image will have been re-sized twice - once by the graphics card and once by the monitor. Instead, you should output full-frame from the graphics card and disable overscan on the monitor.
On most monitors this "just works" because signal hints it receives over HDMI tell it that the signal is coming from a PC, and from this the monitor can infer that it shouldn't use overscan. In some monitors (particularly those designed as televisions) it may be a manual option in the monitor settings however.
Some monitors may refer to this as enable/disable overscan, but at least one some (including my Samsung TV) the no-overscan mode is referred to as "screen fit".