Next idea - Go to CPUID and download PC wizard - http://www.cpuid.com/softwares.html There is a "no installation" version. Its a very handy tool that will show you all sorts of things about your system.
After you download, extract, open the application icon. Let it load your specs and look at network card. It will list the exact make and model of your network card. Then you can search for the specific driver. A lot of the network card manufactures will have drivers listed right on their website.