Just found this possible solution to those of you with grey screens when loading up Q3, RTCW or medal of honour.
- set your screen resolution to 800x600
- set colour to 16bit
Then using control, alt, delete to open the window that shows your running programmes. You need to close down all programs within this window except for Explorer and Systray.
Once you have done this run you can then run the game. This info was acquired from techsupport.ea.com.
Let me know if it works for you.