Removed cover on switch to replace fans. Now no power. Help!?

I had to replace 3 fans in my catalyst 2600XL switch. I removed the cover and wanted to double check which fans were bad. I plugged the power back in and the switch was unresponsive.

Is there a latch or safety mechanism on the switch to keep the power off when the cover is off?

I had not touch or replaced any of the fans at this point.

Any suggestions? Thanks!!