Vista - Driver conflict problem

Hi guys,

I'm having following problem:

1. I'm having PCI slot Realtek 8139/810x Ethernet card and Creative Sound Blaster Audigy 2.

Network card is working just fine. I can switch PCI slots and the realtek network PCI card is working fine.

2. I insert in the secound PCI slot Creative Audigy 2 Sound card.

after reboot i'm able to install creative drivers. Creative card works fine, BUT MY ETHERNET CARD IS NOT RECOGNIZED ANYMORE. It goes in Other Hardware as :
PCI Input Output device . It cannot find any driver. I give in device manager Update Driver. and then the directory of RealTek driver. It doesn't work.

Even if i install manually the realtek driver it still does not work.

After ejecting the Sound Blaster card from the PCI slot the NETWORK CARD works just fine.....

What can be the reason for this problem ?

do you still get the problem if you change them around, so both cards are in a different slot to the one they were installed in??????? (both at the same time)