motherboard not detecting LAN card

[anarchy0x]

hello all, my motherboard will not detect my pci lan card
I know the pci lan card works, as it works on a different computer and is
detected.
Ive tried it in 3 different pci slots with no difference, tried scan
hardware changes and add new hardware, but it just doesnt appear anywhere,
yet its green light is turned on indicating that its working.
other non networking cards are recognised on these same pci slots.
It was recognizing it before but I didn't have the drivers so I clicked on dont prompt me to install this hardware.
I hav tried the add hardware wizard but it doesn't help.
I also tried using the option scan for hardware changes & that didn't work too.
I have tried using 3 different LAN cards but I am still having the problem
Also, the action in driver signing is set on Warn
Help will be really appreciated

[azaad_shri75]

download drivers from the website of your lan card, and also check the card on other computer.

[anarchy0x]

I did that but I cant install the drivers unless windows detects the card & asks me to install the drivers. The card is working fine on other computer. And I have tried 3 cards but same problem.

[ravi_9793]

start-->>right click my computer-->>properties-->>Hardware-->>decive manager.

can you see any hardware with ? or ! sign??

[ashnik]

when did the problem start?