This is a common misconception about laptops. The video section is not on a card but on the mainboard with everything else so no card to be replaced.
If this was mine I'd boot some other LIVE OS from CD, DVD or USB (how is on the web) to see if the problem is hardware.
My satellite pro L550 screen has started to flicker. The top title bar of any application is up top of screen but the main part of the window has moved up over the top of it. The bottom task bar looks like there's 10 on top of each other.
Is this a graphics card issue? The original card is Radeon HD 5145. I cant find one on ebay but there are plenty of different numbers. That look the same card. I dont need any graphics power. I dont play games. Will any of these replacement cards work for me and fix my problem?