I'm running pretty current/sufficient hardware (Quad-Core, 4GB DDR2, NVidia 9600GT) with Vista x86 Business. All software is up-to-date: OS, Firefox/Extensions, other plug-ins like Flash/Shockwave/Java, all my games (via Steam or not). All my drivers (including the NVidia driver, right now at version 260.99) and my BIOS are up-to-date. I am running a dual-monitor extended desktop setup (primary display 1 on left, and display 2 on right). Issue is when Firefox window is either opened on display 1 or minimized to taskbar, I can not play full-screen current games (e.g. Team Fortress 2, Left 4 Dead, Left 4 Dead 2, etc.). However, if I close the Firefox application, or if I move the opened Firefox window to display 2, then there is no problem running a full-screen game. This problem happened, I believe, since Firefox 3.6. Also, I see that there are plenty of other users with the same problem; yet, every post like mine complaining about this issue gets absolutely no response (even ones posted half a year ago; thanks a lot Mozilla, not).