I have tried various fire and ice combinations but I have not even seen a light beam. Any ideas??
Are you on a PC? If you're on a PC there's a known issue with our graphics.
There's a download available if you search the quest name and don't mind having a non Bethesda patch in your game. Otherwise there's a console command that just ends the chain right there so you can move on with the next step.
Likely you also cannot see Clairvoyance or some of the coolest visual effects in the game (at the College of Winterhold those pools of blue light are actually beams shooting up into the sky, for instance... and you may not know this but the floor inside lots of dungeons has mist/gas coming up from it.)
console command is
setstage mg06 55 for exactly that quest and the patch can be found at http://www.enbdev.com
Good luck! As much as I hate patching my own game I'd rather do that than miss out on the amazing stuff I can see in full color every time I watch my roommate playing the game on his 360.
in order... put in crystal, lights appear pointing all over the room... frostbite and flames will adjust the lights (spellbooks are above you on a table if you don't have one or the other or both spells) until there's one light on each of the three lines of the ceiling... go up and adjust the rings where the lights are pointing until there's a light on each of the blue circles to complete the focusing...
and if you're on a PC you can try maddeningly forever, post to the forums and finally stumble on your answer yourself and use the console to finish the quest and move on.