Arduino not detected
Are you sure your laptop doesn't detect any device? It is possible that you need to install right driver for your arduino. The problem could be with:


Cable: Try to replace it with a working cable
Drivers Issue: You need to install driver for your Arduino. Generally, your laptop will issue warnings if it didn't find any appropriate driver for it.
USB-To-UART Bridge: This is an IC in arduino board. It needs to be working for laptop to detect your board. 
Microcontroller: Since, you told us that your board is blinking, then microcontroller will be working for sure.


Can you see any part getting hotter? Have you tried with other laptop and cable?