Vista blocking wireless card?

I am trying to install a Realtek Wireless USB card on a computer with Vista Home Premium. It looks to me like Vista is blocking the installation because it said I'm using an unsigned driver. The user is an Administrator and I've turned off the antivirus and firewall. The card works because I'm using it right now on my laptop using XP Pro.

I haven't used Vista all that much, so can anyone tell me where I can look to push this through? The software included seemed to install fine, so I really think it's the hardware being blocked.

Thanks for your help.

 

Possibly a conflict with the WZC service in Windows.
If you installed software and want to use it, try going into services and disabling the Windows service. (services.msc in the RUN command)

 

Could be simple as driver conflict. Had same problem with realtek usb and vista. Make sure you see the device installed properly (check device manager).