When a user loggs in (Mostly under IE) on the front page it wont send the session data so they get : Please wait whilst we transfere you, then back to the home page and not logged in.
Firefox works perfectly (No mods made at all) so maybe everyone should get that? ;)
If the user clicks the "remember me" button it works no problem and loggs in straight away.
They can also use the /login.php page which also works.
I dont get why this has started happening, all services are fine on the server, MySQL has been recently restarted incase of bad input to it and the PHP system is working fine?
Short of re-uploading from fresh is there any other ideas what is causing this?
Seriously speaking, if it is IE7, disable all "security things" until it works. If IE6, a previously failed login could have been cached by the "browser" so You might need to clear cache and cookies.