What processes on the server are consuming the most memory? the most CPU?
If you need help starting the Task Manager, go to the taskbar where your Start button is, and right-click. Choose start Start Task Manager. Go to the Process Tab, and then you click on the column you want to sort. Check both CPU and memory.
Since it is unlikely (unless the network methodology was changed) that the network has changed or the clients, you need to look at what is going on the main AC machine.
