xxx.xxx file

Anyone know what this folder is? I found it under my C drive. When I open the file there r 2 sub files: stub_data and stub_exe...when I try and open either of these folders...
it says I dont have permission to open them!

Welcome
That file extenstion is usually the cause of registry problems. You can correct with a system restore from before the problem.
http://www.vistax64.com/tutorials/76905-system-restore-how.html
If the restore solves the problem or not run a full anti virus scan and then download and run a full scan with malwarebytes.
In addition if restore does not solve the problem, download ccleaner and try the reg cleaner portion. I do not usually suggest reg cleaners, as they are not usually useful, but ccleaner is the most benign and should not cause any problems, even if it does not solve the problem.