Microsoft stopped maintaining the 13-year-old operating system software on April 8, 2014. 

That means XP is no longer secure enough to use on the UC Davis network—or to use online, period. If you still use XP, you need to move to a newer operating system.

UC Davis policy prohibits use of unsupported OS or application software on machines that connect to the campus network. Unmaintained software is a common entry point for viruses and malware, which can then spread to other UC Davis computers.

See the UC Davis Windows XP Security page for more information.

UPDATE: