We had a server problem the other day.
It should have been a routine fix - the RAID controller card had gone bad and needed to be replaced. Not a big deal.
So I put in the new controller card, changed the cable and replaced the battery pack.
I fired the server back up, and checked the drive array in Windows.
I rebooted to make sure the controller card showed up in the POST process.
Then I spent the next two hours wondering why the card showed up in the POST process but not in Windows.
I reinstalled drivers.
I flashed the firmware.
I rebooted 27 times.
I expanded my vocabulary.
I did a rain dance.
Then I got a bright idea – open the case back up and check the connections.
Sure enough, one cable was pointing straight up, dangling in the air.
It works now.