After the recent Ubuntu update of x2go I'm having some problems with my windows client on Windows 7: Everytime I try to resume a session the screen goes completly dark, even the x2go logo dosn't appear. The only way I can regain graphics is to terminate the session and start it again.
I try then to update the Client to the last on the site and the problem is still hapening. Sometimes I run the install for Windows and the problem is solved but this seems a question of "luck" since this dosn't allways solve the problem.
I have a same problem, about same configuration (win7; ubuntu, xfce). Workaround was to install PyHoca-GUI client to Win7 and I am using this since now.