Shoutbox

Changing the password was all you could do.

The links appeared to your contacts because that website (at least the automated service on that website) logged in using your password and login. It then advertised itself by sending its link to everybody on your contactlist.

However, it can not install something on your computer. At least, not when you have some kind of security system in place which would detect ActiveX controls or whatever being executed from the website.

So the tab changing, slowing downs, etc can well be from something else you did.

I suggest you disable system restore, reboot your computer into safe mode, and do a complete full system scan.

Remove the Windows Live Messenger completely (=uninstalling it from the Add/Remove Programs control panel) and removing its program directory from your computer (to make sure everything is removed).

Then redownload Windows Live Messenger and reinstall it.