Not wanting to get into a debate of Linux vs Windows which has been done to death here and elsewhere it might be sensible not to assume everyone has windows O/s and include an option for "None, I use another O/s".
Having said that...the question is about upgrade, and you can't upgrade if you use another O/s so don't participate in the poll as it isn't aimed at you.
PC Advisor and the FE are at liberty to target polls at any section they wish so I suppose on reflection they are implicitly asking "Of those upgrading or using windows currently......" and if you aren't then don't enter the poll.
If I ask "How many eggs are you eating today" and don't give an option for zero I can only be expecting answers from egg eaters :)
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