You have to check the scheduler tasks and make sure they are enabled and the task is unlocked. Turn on the task log and see what it shows. If you are on a shared host you can not examine the mysql logs to see if these are slow query problems. But you can re upload your IPB forum files to make sure nothing has changed. You can also cahnge minify js/css to no and see if that helps.
Go to your ACP > Look & Feel > Manage Skin Sets & Templates > your skin > boardindexTemplateFindi this: and add BEFORE or AFTER: Edit "title" and "html message here" to whatever you want. You can add images, html code, ads or basically whatever you need.