


Right click on the file and go to 'properties'.
Click on the 'security' tab.
Click 'Advanced'.
Click on the 'Owner' tab.
Click 'Edit'.
Select your user and click OK.
Click OK on the next box.
Then OK on the final box.

Now right click on the file again and go to 'Properties'
Click on the 'security' tab.
Click 'Edit'.
Select 'Users'.
In the bottom part of the box, tick the box to allow 'Full Control'
Click OK then OK again on the last box.

You now own that file and have full permissions over it.

Now simply right click and 'rename' the extension of the file to .BAK
Then paste in your replacement file.