Microsoft says that they will no longer support Windows XP starting on April 8, 2014. See:
http://www.microsoft.com/en-us/windows/enterprise/endofsupport.aspx
for more information. Some IT Security people expect that there are malicious people waiting for that date to take advantage of Windows XP computers. Windows XP should not be used on networks after the support ends.
University owned computers can be upgraded with software available at:
https://microsoft.utoronto.ca/