Just to reiterate, have you read this and installed all the tools and drivers?
For serial
http://docs.spark.io/connect/#connecting-your-core-connect-over-usb
For DFU
Just to reiterate, have you read this and installed all the tools and drivers?
For serial
http://docs.spark.io/connect/#connecting-your-core-connect-over-usb
For DFU