Check if your antivirus didn't move some game files to quarantine. I have also unpacked archive to a random folder in my computer, then I copied all the files and pasted them in system folder (witout deleting the folder). Of course I have overwritten files.
Hello I had some problems like this. I had to unpack system to a random folder. Then I copied files and pasted it to system by hand. Not directly from package to system! If it says that archive is corrupted or damaged, check if your antivirus doesn't move it to quarantine and check your version of WinRAR