Does it pop up at all?
Pull the release handle (inside the car),
Then push down on hood (in front, center) hard a few times (not hard enought to dent)
then try pulling up on it.
All of that doesn't work?:
Check cable inside of vehicle to see if it is actually pulling and not just the lever moving.
Look under the front of the vehicle (or through the grill if you can see it) and locate the release cable and it's connection to the hood release. Try to get a screw driver up in it to push the release catch and pop the hood.
The problem is probably either the cable is binding up along it's path, the cable is broken (at either end) due to being pulled too hard or the latch is sitting out of alignment.