Well, finally there was no problem with the ps2pdf , it's actually the pdf viewer of Texmaker. It's all OK when I use Adobe Reader.
I lost all the day on this
I updated my MikTeK version but the problem is not solved.
I tried to execute directely the ps2pdf command (C:\Program Files\MiKTeX 2.9\miktex\bin\x64\ps2pdf) in cmd and I get what I want
That's weird
I'm a Texmaker user on windows and I have a problem with its ps2pdf function: I use postscript figures produced by gnuplot in my document where I put grec symbols. The problem is that while making the pdf file, some of this symbols changes. I checked the ps file of my report and all the symbols are ...