Xfx GeForce 9600 gso help!

I have an XFX GeForce 9600 GSO fatal1ty edition card

i was upgrading from a EVGA GeForce 7300 LE

when i put in my new card(the 9600) and hook it all up (power cables ect.) i get one long beep and my computer still starts up and all the fans are going even the one on the card. i even hear the windows start-up noises, but i get no display. but when i plug my old card it fires up and i get display no problem. whats wrong with my computer?

i made sure the card was firmly pressed in and all the ram was securely in place.

here is my specs if it helps

Name AMD Athlon 64 3200+
Codename Venice
Specification AMD Athlon(tm) 64 Processor 3200+
Package Socket 939

Chipset
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Northbridge NVIDIA nForce4 rev. A3
Southbridge NVIDIA nForce4 MCP rev. A3
Graphic Interface PCI-Express
PCI-E Link Width x16
PCI-E Max Link Width x16
Memory Type DDR
Memory Size 2048 MBytes
Channels Single

Windows Version Microsoft Windows Vista (6.0) Ultimate Edition Service Pack 1 (Build 6001)
DirectX Version 10.0

BIOS
Phoenix Tech.
V. 6.0 pg
Date 01/05/2006

EDIT: i have a 400w power supply