This thread was originally posted by N2k1 on Elephone

If you have Win 7 x64 or Win 8 (or Win 8.1) you have to disable the sign check in drivers while installation.

Download the Flash Drivers from here: http://n2k1.com/n2k1/drivers/USB_VCOM_Driver.zip

Now you have to unzip the Drivers.

Press the Win + C keyboard combination to bring up the Charms Bar, then click on the Settings Charm.

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We need to head into the Modern Control Panel, so go ahead and click on the Change PC settings link.

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When the Control Panel opens, switch over to the “Update & recovery” section.

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Then click on the Recovery option on the left hand side.

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Once selected, you will see an advanced startup section appear on the right hand side. You will need to click on the “Restart now” button.

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Then head into Advanced options.

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Then Startup Settings.

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Since we are modifying boot time configuration settings, you will need to restart your Computer one last time.

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Finally, you will be given a list of startup settings that you can change. The one we are looking for is “Disable driver signature enforcement”. To choose the setting, you will need to press the F7 key.

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That’s all there is to it. Your PC will then reboot and you will be able to install unsigned drivers without any error message.