First, are you sure you used a 15v power supply?
Now, there are a few things we could check to see if your board is still functional. If you connect the Edison to both USB ports, are you able to see both ports in the device manager?
Are able to read the Edison's flash drive from Windows Explorer?
Are you able to access the Linux shell?
You might just have run out of space on your rootfs. Every time you upload a sketch, data gets logged at /var/log/journal. The logs are persistent, so if you're already low on space your free space can get soaked up. Check the available size with df -h, you'll be interested in /dev/root.
Remove the logs manually and you'll be ready to go again.