|The card should have its own bios that will take over after the HP bios' posting process. Do you get that secondary screen when the card bios does the drive search?|
Are you using an 80-wire cable and, if it's a different cable than you used with the on-board setup, are you sure the drive is connected and jumpered right for that cable?
Describe the card. I had a problem with an old ATA card that I think was for a raid setup.