just found what I needed in the security centre, it gives the option to how windows informs you about security issues.
That's not the same warning that your original post outlines.
That's merely telling you if your AV, Firewall or Automatic updates are working/up-to-date.
"Not if you have a genuine copy of Windows"
Now god forbid that I should say the guy from M$ gave you false info.
But, assuming he is correct, then you need to be careful, otherwise just by removing the nagging reminder does not bypass the fact it is or may be a iffy copy.
So, before you spend hours/days installing all your software and updates, make sure you follow TD's instructions and are then able to install any M$ updates by passing the WGA check.
Otherwise, you may find in 30 days time your PC boots into a black screen giving a warning message which you then have to acknowledge, which I believe also pops-up very frequently, and you end up back to square one.
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edit
Unfortunately TD's link does not seem to go directly to the DL site.
So once at Softpedia just type "RemoveWGA" into the search box at the top of the page and it will take you there.