Why not? I am using Opera 36 on a Windows Vista machine without any problems.Why would you expect to be able to use a 7 year old version of a browser?
If TheKrell needs a new browser (compatible with Windows XP and up) there is Mypal (which is based on Firefox Quantum). You can also use Mozilla Adds-ons. Certainly better than using IE!
Mypal - Official Website
Official website of Mypal, the up-to-date web browser compatible with Windows XP computers.
www.mypal-browser.org