WiFi Failing and Keychain crashing
A friend of mine had a similar problem. After trying the usual fixes (restarting, removing wi-fi networks, removing wi-fi network interface, resetting PRAM and SMC, deleting login keychain from ~/Library/Keychains/login.keychain), I was able to solve the Keychain Access crashing (and wi-fi issues) using a solution from here: http://www.unsanity.org/archives/security/love_tropicana.php

In short, remove the wi-fi network (from System Preferences > Network > Advanced > Preferred Networks), then open Terminal and type in these two lines:

$ sudo mv /var/db/CodeEquivalenceDatabase
$ /var/db/CodeEquivalenceDatabase.old


(For more information, read the page I linked to above.)

Then restart, and see if Keychain Access opens - it did for me. You can then delete any passwords or certificates related to your school's wi-fi. Then try connecting to the network again.