Folks,
I've USB problem too with Galileo Gen 2. When I boot it without SD-Card, I can only detect it on my PC (Win 7 64-bits) for the first time. If I unplug the USB or reboot the board, the connection will be forever gone (can no longer recognize the board on the same USB port) until I reboot my PC.
One consistent work-around that works well for me so far is to boot from SD-Card.
1. Download the image - LINUX_IMAGE_FOR_SD_Intel_Galileo_v1.0.2.zip.
2. Unzip the file into a micro-SD (it takes about ~300MB).
3. Plug it into your SD-slot on Galileo Gen 2
4. Reboot (it takes about 1 minute for this process)
With this, my USB connection seems very robust to date. Connect/disconnect the board and rebooting the board doesn't give me any problem anymore.
Hope this works for you as well.
