Slicer will not work HALPPPP

So every file I download in creality or cura is fine until I go to slice it. Once it’s sliced it has white rectangles and pink little circle things in the file. I have been on you tube and searched and search, uninstalled and reinstalled and the only thing that I just came up with is that it maybe a setting in my firewall that is preventing this. Does any one have any ideas if this is what it could be or have heard of this before? I am running it on windows 10 and even purchased a file that i knew would be good and am still having this problem.