Liam, I dont think that your stupid, however you would be amazed at how this equivalent of "is it plugged in?" fixes people because for some reason many people don't try the obvious first. You know much like how people don't like telling us the pieces of information that we actually need to troubleshoot things. Such as the version of osTicket, PHP, or mySQL that they are using, or if they have tried different web browsers, etc. Do you have access to your MySQL or webserver error logs? I'm wondering is there is an error being reported there. It sounds like a problem with sessions to me.