After updating to Maverick 10.9.5, I can no longer access my school's WiFi. How can I fix this problem?

I recently updated my Macbook Pro 15" to 10.9.5 Mavericks, and now I cannot connect to my school's public WiFi as before. The WiFi log-in popup window appears but nothing happens. This is a big problem for me because I have my books & notes online and now I can't use them in class. I really need some help to resolving this issue. Specs below:

MacBook Pro, OS X Maverick (10.8.4)

15-inch, Mid 2009

Processor: 2.8 GHz Intel Core 2 Duo

Memory: 4 GB 1067 MHz DDR3

Graphics: NVIDIA GeForce 9400M 256 MB

Thanks in Advanced,