Check Ubuntu version from GUI
Here are the steps to achieve the task:
1. Click on Settings menu either from top right menu or from button in left bar.
2. This will open System Settings dialog window.
3. Click on Details icon which is in the System category. Look into screen shot for more details.
4. This will open System Version Dialog where you can see which version of Ubuntu are you running. Also you will be able to see processor, RAM, HDD and whatever you run 32 or 64 bit version of Ubuntu.