I've been using Ubuntu 12.04 with no problems for the past 2 months. A few hours ago, when i restarted my PC, it just hanged with black screen for more than 10 minutes. So I did a hard reset by pressing the power button for a few seconds.
However, when I now start the PC, Ubuntu loads till the Ubuntu logo with 5 dots under it, then remains there forever. Tried several times with same result.
I tried Boot-Repair recommended repair, but it didn't solve the problem. Here's the URL it gave to ask people for help.