After a clean installation of Windows 7 Ultimate on a new Dell Precision M2400, I was unable to complete an online activation. The specific error “0x80072F8F” provided no information as to the cause of the problem. More information suggested there was a ‘Security Problem’.
After researching the issue I found Microsoft Knowledge Base article 929458 which states that the error is caused by an incorrect time, date or time zone being set on the machine.
The solution is to open the clock properties, select your time zone then select ‘Internet Time’ and update. I recommend selecting “time.nist.gov” as your NTP server as time.windows.com tends to regularly time out.