We are racking our brains trying to figure this problem out an are currently stuck!
Basically we are having issues with some users taking ages to log in in the mornings, some times up to 20 minutes, we have tried correcting this problem looking at a variety of methods, we have checked DNS (seems to be fine, although not my strongest point I will accept suggestions), checked network speed (seems fine), the users in question are not using roaming profiles and there are no policies pointing to unavailable mapped network drives.
This is now a major problem as so many users are complaining that they can make a cup of coffee before the computer logs on.