How can I deal with weird result? XeLaTeX, LuaLaTeX not working

Question

So, I have been using TeXstudio for my LaTeX documents and MiKTeX 2.9. I opened some documents that I created in the past and I see that using XeLateX a weird result at the top of the first page is visible, and I could not find anything similar on Google. So after that I tried with LuaLateX but this never produced a .pdf and gave me a number of errors.

Result with XeLateX

I thought that it might had something to do with the environment variables in Windows because I installed Python yesterday, but I have changed this many times. Also I reinstalled both MiKTeX and Texstudio. Any specific help, or in general? Thanks.

UPDATE:

I have deleted all the files before and even copied and pasted the file in a new folder to run it like a new project. I forgot to point out that probably a part of the problem is the \usepackage{xltxtra}. For instance with XeLaTeX, when running the code below, the result is normal.

\documentclass[12pt,a4paper]{report}
\usepackage[utf8]{inputenc} 
\usepackage{amsmath} 
\usepackage{amsfonts} 
\usepackage{amssymb} 
\usepackage{geometry} 
\begin{document} 
    This is some random text for preview purposes. 
\end{document}

But using \usepackage{xltxtra} the result is same as the one pointed in the question.