Windows 8 introduced universal drivers and standards for the Bluetooth(r) SMART protocol used by Emotiv Insight. All SMART devices used with Windows 8 now use a common interface which is managed by the operating system, and anyone making SMART receivers for use with Windows 8 comply with the standard.
Unfortunately this is not the case for Windows 7. Each hardware manufacturer providing receivers uses their own standard and this can change between different devices made by the same manufacturer. There are no standard drivers available for Windows 7, therefore we have many users who can't manage to connect with Windows 7 even if they have a SMART receiver which can detect your Emotiv Insight.
We are working hard to identify and provide support for specific hardware devices which have a stable interface for SMART connections. The device we are working with is the Plugable unit available here http://www.amazon.com/Plugable-Bluetooth-Adapter-Raspberry-Compatible/dp/B009ZIILLI and we will announce when support is available for this device in Windows 7.
You may also consider using an Emotiv Universal USB Receiver. See our article https://emotiv.zendesk.com/hc/en-us/articles/204814619-I-don-t-have-a-Bluetooth-r-SMART-BTLE-compatible-device-what-do-I-do-