NEED HELP INSTALLING VIDEO GRAPHICS CARD

i have a radeon hd5450 video card that i want to install onto my pc but when i put the card in the slot and turn it on, it comes up with a black screen (dosent even sound like its booting up) ive tried installing the drivers first but nothing ive even disabled the on bord graphics. can somebody please tell me what im doing wrong. any help is appreciated.

COMPUTER SPECS

CPU speed: 3.8 GHz
Memory: 1 GB
Hard drive: 120 GB
CD / DVD: CD + DVD writer

#AM2 3600X2 CPU
#1GB DDR2 RAM
#120GB Sata HDD
#The on-board NVIDIA Quadro NVS 210S video + DVI
CPU:AMD Athlon 64 X 2 3600+
RAM: 1GB DDR2 (4 Slots 8GB MAX)
HDD:120GB Sata
USB: 6
SATA Ports: 4
GRAPHICS: The on-board NVIDIA Quadro NVS 210S video
Motherboard: Awesome MSI K9NBPM2-FID AM2 Socket
PCIE X16 port : 1
PCI port :2

no i did not disable the onboard graphics card as it will not allow me to, there are only two options wich is. use both vga's (pcie and onboard) or auto which swictches to only one vga. also tried uninstalling the nividia graphics but still the same problem.

When you install the card, did you see what happens when you plug in the monitor to the onboard graphics? Maybe it still isn't being disabled.

i cant disable the onboard vga i can only switch it to auto or dual in the bios and both settings seem to make no changes. although i was just woundering if maybe i need more ram, i already have 1gb but it wouldnt hurt to get two. anyway here is a link http://www.sapphiretech.com/presentation/product/?leg=&psn=000101&pid=313

Did you plug your monitor into the onboard DVI port to see if the onboard is still the main card when both are on?