Problem with my newly installed Video Card

Hi have this problem in my newly installed video card from NVIDIA GeForce 7300 SE/7200 GS.
Everything is in default but every time i start my PC, there's white horizontal lines occurs on start up and when i open random explorers.
I'm worried about what can it be done to my monitor.
I checked the plug on the motherboard, its tight.
How can i fix this?
