Hello Rebecca1988,
I did a little research on your system and newly purchased graphics card. I'm sorry to inform you that the two are not meant to be together. There are different versions of the PCI Express bus. The system you seem to have has two PCIe x1 slots. (based on what I got from the support page for your system) The graphics card you bought has a PCIe x16 edge-board-connector. Much larger than the slot on your system board. Any of the previous PCIe bus versions will work in a PCIe x16 but not the other way around. Basically the graphics card you just bought will not work in your system. The only thing you can really do is find a way to return in it or when in doubt...eBay. What you would need is a graphics card for a PCIe x1 bus. You can also stay out of your computer tower completely and purchase an external graphics card that connects blissfully into an available USB port, not sure about the quality though.
ALSO, if you still plan on upgrading your graphics card in the future. Pay very close attention to your system power supply. Many people make the mistake of buying a big and bad graphics card (and then bragging about it) but pay no attention to the amount power it needs from your system's power supply, and thus their system does not boot or even power on. Some cards will in fact give you a recommended power supply rating on the box, but many don't it's always good to research that. Not many people like to spend more than what they need and/or can afford. For example, you buy a graphics card that calls for a minimum power supply of 350 Watts, (which is quite common for graphics cards over $90) where your system's power supply is rated for only 275 Watts. Obviously it's not gonna work. The higher quality the Graphics Processing Unit (GPU) is the more power it needs.
