On Windows 7 it may happen that you are denied access to files that you regularly own and have permission to write to, even if you are logged in as administrator, perform the action as administrator or from an elevated command prompt or try to access it in safe mode.
If this happens to you and you have already tried all usual means, as changing ownership or use Unlocker on it, there is a fix for you that circumvents NTFS security to access the files called AccessGain Tool.
Download it from here: http://www.hobeanu.com/blog/accessgain-tool/
Before you follow the installation guide in the readme-file, reboot your computer and choose the advanced boot options on F8. Select Disable Driver Signature Enforcement there to be able to use the tool properly.
Be careful: This tool grants you access to any files stored on your file system - do not delete any files that you do not know the purpose of!