” We have noticed some unusual activity in your account. Your action is needed to make sure that no one else is using your account”

When I open my windows live mail using the icon on my desktop, a pop up shows up with this. I cancel or X it out. When I go into webmail this does not occur. I have contacted my ISP and Microsoft and got no help. I deleted the account and have added another e-mail account and it still pops up. I have ran full virus scans, malware, spyware and adware ,.... I never hit the OK button when it came up. I have seen this question from last year, but no answers. Any suggestions. Thanks so much!