From;
http://download.cnet.com/1770-20_4-0.html?query=Oxford+Dictionary&tag=srch&searchtype=downloads&filterName=platform%3DWindows%2CWebware&filter=platform%3DWindows%2CWebware
I see a number of different options for Oxford English Dictionary.

Which one are you talking about?

If it is this one;
http://download.cnet.com/Oxford-Dictionary-of-English-Second-Edition/3000-2279_4-10238904.html
then I looked at the "Full Specifications" page and saw it was a 10-day trial only. I usually stay away from those.
http://download.cnet.com/Oxford-Dictionary-of-English-Second-Edition/3010-2279_4-11109114.html?tag=mncol

Mark