I'm pretty sure the Intel wireless driver is the wrong thing. I have an Intel chip in my netbook and the wireless driver is not Intel. (Mine is Qualcomm Atheros). Uninstall that Intel thing and try to install Realtek again -
if you are positive the wireless is Realtek. If it doesn't work, I don't know what to tell you.
You either have to plug the laptop in if you want to listen to audio, download what you want or listen on a supported device. (Vista hasn't been patched since April and with all the nasty stuff on the internet, it's better to use a patched device on the internet).
It also bother me that you have Network Controller with a problem. That could be related.
can you help me resolve this error 31 and get wlan going again?
Probably not. If you can't get the correct driver from Sony to install.
This link is for US. Start here,
Sony eSupport - Drivers & Software Updates - Select a Model
and click Detect my model. Perhaps it will download the drivers that are missing.