I run a Dell desktop running Vista and a Dell Laptop running Windows 7. On both machines I run Windows Live messenger and up to a couple of days a go there has been no problems. Then for no obvious whenever when I sign into Live Messenger on the Vista machine it takes me to a windows secure site:
to renter my password again for security reasons. This takes me to my Inbox and all is ok. My Laptop does not take me to the above URL it just goes into Live messenger as normal. My question is why does this happen and how to stop,sorry if the mail seems ro ramble.
I would be concerned about the redirect - supposedly for security reasons - it may look genuine, but could be harvesting your password. Sometimes Windows Live may ask for confirmation for real, but it doesn't usually do it every time.
On your Vista machine download, update and run Malwarebytes from here