Please say what keyboard you use and most importantly if it has keylock or not. To test it : http://www.microsoft.com/appliedsciences/AntiGhostingExplained.mspx For exemple 4 arrows + space at the same time and see if they are all accepted. I'll update this post to make a list.
No keylock : Logitech G11, G15, Logitech media elite, Microsoft Wired 500 (Numpad), Dell Sk-8100, Razer Tarantula
Keylock : All Cherry models, Logitech G15 Refresh, Logitech Ultra-Flat
