i can't open WiFi on toshiba satelite a665 after updating to windows 10

Solution
The most likely reason is that the Windows 10 Technical Preview does not have a compatible driver, and neither does Toshiba on their website. Laptops can be particularly problematic where drivers for new Windows versions are concerned because their hardware components cannot be upgraded to make it compatible where required.

Whilst many Windows 8 drivers will work on Windows 10 TP, the same can't be said for Windows 7 drivers.
And Toshiba won't release any Windows 10 drivers until Microsoft releases the RTM version, some way off yet.
Even then, Toshiba may decide to exclude your particular Satellite series..

Remember, Windows 10 is still in it's testing stages, you can't expect everything to work as it did before, and you shouldn't...
The most likely reason is that the Windows 10 Technical Preview does not have a compatible driver, and neither does Toshiba on their website. Laptops can be particularly problematic where drivers for new Windows versions are concerned because their hardware components cannot be upgraded to make it compatible where required.

Whilst many Windows 8 drivers will work on Windows 10 TP, the same can't be said for Windows 7 drivers.
And Toshiba won't release any Windows 10 drivers until Microsoft releases the RTM version, some way off yet.
Even then, Toshiba may decide to exclude your particular Satellite series..

Remember, Windows 10 is still in it's testing stages, you can't expect everything to work as it did before, and you shouldn't be using Windows 10 TP on your main everyday computer anyhow.

From Microsoft on Windows 10 TP:

"It Won’t Support All Hardware & Software

Windows TP was designed with modern hardware in mind and comes preloaded with a limited number of drivers. Remember that it’s an evaluation copy for enterprise users. They are using Windows 10 TP to examine compatibility with their existing setup and to make requests to Microsoft for changes. As a result, Windows 10 will go through a number of changes before its final release in mid-late 2015. A Developer Preview of Windows 10, based on which new software and hardware drivers will be developed, is expected to be available for Microsoft’s Build conference in April 2015.
Once the final version of Windows 10 is released, it will contain a wider selection of hardware drivers. Likewise, software will be updated to work with the new OS and make use of its novel features. Meanwhile, Windows 8 drivers and software should work fine on Windows 10 TP.
"

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Have a look on Toshiba's website to see if they have any Windows 8 drivers for your model. If they do, try the network drivers.
 
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