I just got back from a job with some windows genuine activation problems.
As usual i just googled a bit and tried with the command prompt to get rid of the pesky notification bar.
The issue at hand had to do with volume licensing .
Turns out that if you have a valid key there is an online validation checker if you go to the help section in the activation window.
Bottom line is if you have a valid key just go here and save yourself the trouble of the activation by phone.