I cannot connect to the internet wirelessly on my Toshiba A205 laptop. I've run the diagnostics and it seems the adapter is not working. When I look at the system I can only see the Marvell Yukon PCI-E ehternet controller. That is not the wireless, is it? I think I could change it but I'm not sure which to get and where it is.
That is probably the wired ethernet adapter. Have a look at Windows Control Panel, System, Hardware, Device Manager and see if you can spot the wireless adapter.
Have a look at the Tosh manual and see how you switch on the wireless -- usually an Fn key combination or a physical switch on the case.
Go to Toshiba site (or look on any CD which came with the laptop) and download a driver that is for the wireless in your model of laptop -- and appropriate to your version of Windows. The driver may be part of a multifunction chipset but the driver descriptions will say.