Steps:
1. Select any file you want to take ownership.
2. Right click and choose "Properties".
3. Go to "Security" tab and click "Advanced".
4. Go to "Owner" tab, click on "Edit" and choose your username. Afterthat, click Apply.
5. At "Security" tab , click "Edit"and a box of list of users will popup. Click at your username (created on step 3), and check the box titled "Full Control".
6. Click "Ok"
Done.