asus essence stx not recognised on booting win8 but ok when reseated on pciex1

[kalijaga]

Gurus, i have a problem witn a dell xps 8500 running win8 that is not recognising my essence stx on bootg, but if i reseat the card while the pc is running, it will be detected n work like a charm. I have changed to different pcie slots n i have disabled on board audio n other sound drivers. Other cards installed are gtx 680 n mini pci wifi card. Thanks for any ideas short of reinstalling win8.