Typesetting low-resolution text only - LaTeX

Question

Having read this question I have not managed to find any solution to my problem, so decided to make a new post.

At first, consider the following code:

\documentclass[11pt,a4paper]{article}
\usepackage[english,greek]{babel}
\usepackage[iso-8859-7]{inputenc}
\usepackage{amsmath,tikz}
\title{\foreignlanguage{english}{On the explanation of my Problem}}
\author{Μάρκος Βασίλης}
\begin{document}
\maketitle
\section{\foreignlanguage{english}{Latin text}}
\foreignlanguage{english}{Latin text Latin text Latin text Latin text Latin text Latin text Latin text Latin text Latin text Latin text Latin text Latin text 
Latin text Latin text Latin text Latin text Latin text Latin text Latin text Latin text Latin text Latin text Latin text Latin text 
Latin text Latin text Latin text Latin text Latin text Latin text Latin text Latin text Latin text Latin text Latin text Latin text, 1}
\section{Ελληνικό κείμενο}
Ελληνικό κείμενο Ελληνικό κείμενο Ελληνικό κείμενο Ελληνικό κείμενο Ελληνικό κείμενο Ελληνικό κείμενο Ελληνικό κείμενο Ελληνικό κείμενο 
Ελληνικό κείμενο Ελληνικό κείμενο Ελληνικό κείμενο Ελληνικό κείμενο Ελληνικό κείμενο Ελληνικό κείμενο Ελληνικό κείμενο Ελληνικό κείμενο 
\section{\foreignlanguage{english}{Math}}
\[\ln x\leq x-1,\ x>0\]
\section{\foreignlanguage{english}{Tikz}}
\begin{tikzpicture}
\draw[thick] (0,0) circle (1cm);
\draw[thick, draw=red] (0,0) circle (1.2cm);
\end{tikzpicture}
\end{document}

Now, when typeset, it gives the following result:

If we zoom a little bit on each paragraph we will see that, despite english, math and tikz content are diaplayed in the usual high resolution of LaTeX, greek text is as follows:

Also note that 2018, in the date section of the title appears in low-resolution but, when in latin, it is allright.

So, how could I also have a greek text of equally high resolution? Note that I could typeset normally in the same resolution with my previous installation of MikTeX and, despite installing the same version (2.9), I got this problem, now (typeset with pdfLaTeX).

So, any help would be pretty much appreciated! Thanks in beforehand!