|"can someone tell me what is wrong?"|
Sure, you didn't do enough research BEFORE you bought the video card. Why didn't you just open the case beforehand & have a look? Other than that, how do you expect any of us to know what you have? You didn't bother to list a single bit of info about your system. Is it an OEM machine (Dell, Gateway, eMachines, HP, etc)? If it is, what is the make/model? If it's a custom build, what is the make/model of the motherboard?
Don't confuse PCI-e with standard PCI. Have a look at this: