Whenever I start up Cross Fire, a blank pop up just, well, pops up.

L1nk1nHax0r

I run it as admin and press Start Game, as usual, but then this comes up...

xPeeka_x

it means ur game gaurd is failing with something.
it happens to me, but i jus deal with.

Joke16

All you need to do is go to your taskbar and turn off the gameguard icon ( as in exit it ) before you start the game.
It should work
If you cant find the icon wait a bit and restart again
by wait a bit i mean about 10 mins

eul0gy

exactly what boosh said. but if your still having the problem and the game guard icon isnt in the task bar, just log off, then log on again, it should work.

0wage2

lot people got that, when it pop out click ok and a web will come out and tell you what to do.

PainCF

Try using game booster, it fixed my problem I was having like that. It is being discussed in the guides section, here is a link http://forum.z8games.com/showthread.php?t=11524