I'musing K2 (latest release) with Cubase SX3 (also latest release). Suddenly the GUI of the default K2 module (32 channel version) will not appear anymore. Works fine fine eith the 8out and 16out version. When pressing the "e"-Button, the icon is highlighted and Kontakt even appears in the window menu...but is simply NOT there.
I already de-installed K" and reistalled it. Same problem. I Installed Battery 3 yesterday. I am wondering if this has anything to do with it? Haven't used K2/Cubase for a while, so I can't say if the problem is related (i.e. I cannot state that K2 ran fine the day before yesterday...).
I Don't know if this will help you but the only time I had a similar sounding issue w/ GUI it had to do with not setting the colors high enough for the display. On the MAC side you have to set the colors to millions...I'm not sure if there is a similar situation on windows.
Hope this Helps