Mandriva distro, which one? What kernel version are you running (if you don't know, just type uname -a in a command prompt). Look at dmesg (dmesg in a command prompt) and look if there is anything suspicious. Try uninstalling/blacklisting ndiswrapper/the native driver (iwl4965?). Check your configuration files.
Try scanning for wireless networks when you know you should see one (iwlist scan), if you see one, you just need to configure properly.