Windows shows various files in blue and green colors to show that these files are encrypted and compressed respectively.
That is when windows encrypts a file it is shown green in color and when a file is compressed it is shown blue in color.
This might be annoying and hence, if you do not want these kinds of colors in windows you can disable them by following the below instructions:
Go to folder options in control panel in windows.
Go to the view tab and then uncheck the Show encrypted or compressed NTFS files in color check box and now you will not be able to see any colored files and folders.