Go to device manager and uninstall onboard drivers
Disable onboard sound
See if hardware manager picks up your card
Load your install suite
If that doesn't work download DriverSweeper
Restart in safemode
Run DriverSweeper and purge all previous sound files related to your application
Load your card suite
If none of that works you've got me buddy
Assuming all your hardware and connections are correct.
Your system came with default sound drivers most likely Realtek or something else.
When you add a discrete sound card you will most likely have a conflict unless you disable your onboard sound drivers.
We could help you if you give us more info on your setup.
Such as make of pc ,motherboard manufacturer and model #
and make and model of your sound card