You can get rid of it by taking ownership of the files/folders in question. See this tutorial
for how to create a menu shortcut to do that.
Also, you can look in the properties of the file or folder in question and edit the permissions (for each user) under the security tab.
Also in properties, check and optionally change the attributes, such as whether the file is read only or not.
There is also a free portable tweaking app called the "Ultimate Windows Tweaker
" that gives one an easy way to add (or subsequently remove) "Take Ownership" items to the explorer right click context menu.