PCI-E slot is not working

One night, i let my computer go to sleep (shut down) after a long day. The next morning, i woke it up and it couldn't open its eyes. My computer starts up normally, but somehow won't display the picture. I test everything and knew the machine works alright, because i could hear the log in music. I open my computer and switch the graphic card to the second PCI-e slot, and the picture is back to normal.

Is my PCIe slot that won't display picture "fried"? I'm going to put another graphic card (my is SLI), does that mean i can't do that anymore?

Very likely.

Wow, thats a bummer, But Consider looking in your BIOS and maybe reset the settings relating to it and try again.

Dust on the terminals could also do this, make sure its not dusty.