Well, try a different browser and the other Flash version. I'm pretty sure it will remove the issue. You can also uninstall your current Flash version via Windows & re-install it from Adobe's site.
The issue seems clearly Flash-based. You can write in the forum here, because the forum is HTML- and text-based, not Flash-based. Same goes for your profile page. But the left-hand panel on the forum pages, the log-in window, and the game window itself, those are all Flash-based, and that's what's not working properly on your system right now.