Using the software

I have a problem with Tekla Structures 15. I was workin on an exercice when, suddently, the blue-print view become in 3D. I tried to to put it back to normal... Result, I'm no more able to select anything except the axes grid. I don't know what I did... Look at the screenshoot, it has those two magenta lines whit that XYZ thing in the corner, what is that! Do I created a thermonuclear reaction doing a shortcut accidentently? https://cfpmb-my.sharepoint.com/:u:/g/personal/cotep652_cfpmb_net/EatD0jPSP4hOgfRVbbaQAt8BC_dPSwmXC7Gkkzh4PbVt8w?e=TdqKVT Tank-you for your help.

I install the program, and try to open it and i did. There is no problem so far. But when i try to open a new model this screen pop up when loading screen is about the end. After that i click Tamam(thats mean ''ok'' in our language) program automatically close the program. My system spec is; Win 7 (sp1) 8gb ram, GPU geforce 333m it's worth reminding ; i have the last version of net framework and all the microsoft C++ visuals like 14 of them(2008- 2015) Can you guys solve my problem i'll a lot appreciate you sincerly,