ST2410 Monitor display size

My Dell ST2410 monitor is connected to a Studio XPS desktop with a Radeon HD 4350 video board. I have it set to 1920 x 1080. The display does not fill the 24 inch screen?  There is a one inch black border of unused screen on top, bottom, and both sides? Anyone know why? I'm only getting about a 22 inch picture instead of 24 inches.
* Your Aspect Mode in the video card is not set correctly
* Right-click your desktop, and open the Catalyst Control Center
* Set it to advanced mode if it's not already
* At the top left, click the Graphics menu
* Click Desktops & Displays
* For your desired display, left click the little black triangle in the bottom part of the screen
* Click Configure
* This part is very crucial. There is a little picture of a tiny Monitor and tiny Arrow at the far bottom left of the CCC menu. It is this tiny Arrow that you left click on by the button that says Basic and the button that says OK. When you click on the little black arrow (not the Big Black Arrow in the middle of the CCC window, you will get the option to click Configure. Then the following 6 buttons will be available to you:
Attributes
Avivo Color
Scaling Options
HDTV Support
LCD Overdrive
Pixel Format
* Under Attributes, check the Enable GPU scaling box and the select Scale image to full panel size
* Click Apply
* Under Scaling Options, there is a slider bar to set Underscan and Overscan. Set Overscan to 0%
* Click Apply- OK

Also, when the machine times out and goes to sleep, the display shows a message that says "No HDMI cable". What is this? I have the display connected to the 4350 with an HDMI cable.
* Right. When the PC is in sleep mode, the video card is not transmitting a signal, thus the monitor says, "No HDMI cable"

THANK YOU! I have been about to have a stroke for the past 24 hours trying to fix the monitor! Even did two different system restores.

Bless your heart, Chris M