Right click on the taskbar
Click on 'Properties'
Make sure 'Auto-hide the task bar' is un-checked, and
'Show the clock' IS checked.
Then, click 'OK

You might have to re-boot. I don't know why re-booting should work, but sometimes it's what you need to do to make the evil spirits go out of the computer and back into the car or wherever it is they normally hang out.