I am assuming that one of those websites is the webmaster-talk site?
I am not sure what might be the problem. But could you try one thing, PLEASE. Go to control panel --->Internet Options--->click the tab [privacy] ----if not already set the scale to except all cookies.
You sre right chancess are that this is already done. But there is a difference in "cookies". there are first party and third party. if the settings are not set properly you might have the problem that is occurring
I hope this helps
Toby