If you don't have resources assigned, then % Work complete as well as the traditional Earned Value methods will not be available to you.

Even without resources, you should be able to tell whether you are "on track" or not. Save a baseline (which I believe you have) and make sure you are accurately updating progress. If the resource says they are 50% complete on a 10 day duration task - ask them to confirm they will have it complete by DateX. If no - adjust the remaining duration.

You should not have incomplete work in the past. If a task was scheduled to be completed by Tuesday and it is now Friday and the task is not done - you need to extend the duration by increasing the remaining duration or splitting the task at Tuesday and rescheduling the remaining work to start Monday.