Recently - within the last week or so - I've started having weird graphical issues with STO. My screen frequently flickers and freezes for a second before recovering, and sometimes goes black for a second before returning with a message that says the display driver crashed and had to be restarted.
Within the last couple days it also started having complete graphics freezes - not the whole computer, just STO - and the only way to fix it is either end STO's process or press control-alt-delete (opening that Windows 7 screen) and then cancel out of it. That usually forces it to start working again.
I'm Running Windows 7, have an Nvidia GeForce GTX 260, and just updated the driver for it today. I haven't gotten a display driver crash since doing so, but it froze and i had to ctrl-alt-del it just a couple minutes ago.
Note, this is running in DirectX 9 mode - DirectX 11 seems to behave better, but it also has ugly black missing-texture bits all over everything, so I've been avoiding it.