the chances are probably high (and i mean PROBALBY, its just probably myth or my brain washed saying me that this is a virus)
Viewing post in almost my heart stopped when i tested this
If at least one game client is not working, check the status of the webserver. Try pressing the "Start PHP server" button, you will be asked to start "Start.bat", you must agree to start, otherwise the game will not work. (P.S. after exiting the launcher, you will be asked to start "Kill.bat", you must agree to kill the php server, otherwise for all the time you spend for with your computer (until it turns off), you will have this webserver running forever and loading your PC, AND IN THE Kill.bat and Start.bat BATCH FILES DO NOT HAVE ANY MALWARE. YOU CAN OPEN THESE FILES IN WINDOWS NOTEPAD AND CHECK FOR VIRUSES (Look in launcher>data>webserver))