Horizontal Lines

1HF730DISPLAY..., FLAT PANEL DISPLAY..., 20W, 2007WFP, BLACK..., DELL AMERICAS ORGANIZATION...

1NR603CARD (CIRCUIT)..., MULTI-MEDIA..., AUDIO..., SB0467

1RD729CARD (CIRCUIT)..., MULTI-MEDIA..., TVT3CR, LEAD FREE...

1HH748CARD (CIRCUIT)..., GRAPHICS..., 256, 7900, GS, HMGA14

 

My computer came with Windows XP, but I upgraded it to Vista ... I may be going back to the XP soon.  Anyway, for weeks now, off and on, I have been getting black horizontal lines on my screen and they are starting to get very annoying.   They pop up everywhere.  Also, when my computer is booting up, on the black sceen you can see a whole bunck on pixels  showing in different colors.  Sometimes you can see it on web pages too. I am including pics so you can see what I am talking about.  I uploaded pics to this link ...  http://community.webshots.com/user/EliciaJ35             Is my video card bad or is it the monitor? 

 

Also, another problem I am having now is when I have my mouse pointer on the task bar, on one of the tasks, a little pop up window, showing what that is, shows up, which is fine, but the all of a sudden there diagonal lines coming out of it and going towards the center of the screen.  This happens with all of my messenger screens too.  What causes that?   Someone Please help me.  This is driving me nuts!!!!