I updated it via PSO2 Tweaker just today. After the update I tried to launch the game, which took me to the normal "Game Start" menu, but when I tried to run it, it told me "PSO2.exe is already running" and gave me no other option but to hit "ok." In checking my running processes, I noticed that when I launched the game from Tweaker, it opened PSO2.exe as normal, and when I told it to launch the game, it launched another PSO2.exe, so this message is true. However, when I hit "ok," it auto-quits both PSO2.exe's, and fails to (obviously) launch the game.

I used Tweaker to check for deleted/empty files, for problems with Gameguard, to check for old/missing files, and to fix the PSO2.exe, but this still is happening. I never installed any mods, so shouldn't be an issue there.

Computer is Sony Vaio, 8 GB RAM and NVidia 3300M graphics card, never had any issues in running before now.