I've been having a wierd issue with some Dell Optiplex computers at my workplace. The issue I've been having concerns the fans spinning very fast and loud as if the computer is going to take off, but yet the computer doesn't boot up, the power light turns yellow and the fan moves loudly. I've had this happen on at least 3 Dell Optiplex 320 computers. I even had one happen in a newer Dell Optiplex 380.
What I did was unplug the computer and then I would go into the system and pull out the plug from the power supply. Then, I would unplug a few other things such as the hard drive and reseat the RAM. After doing that it seems like the fan is real quiet like it should be and then boots up normally.
I don't know how that would solve it, but why in the world would this happen in the Dell Optiplex systems? What does this loud and fast noise from the fan mean? It seems like this is the only issue I've been having with the Dells so far and it's the exact same issue on these 4 systems.