We got a second secondhand Mac Pro recently, and I was mucking about over the weekend with it. At one point, after taking out the RAM to clean inside, I noticed it seemed to think it only had 2Gb instead of 4Gb. (I’ve got another 4Gb on order.)
Then I noticed the flashing red light from where the RAM is plugged-in. PANIC TIME!
No, wait, calm down. But a quick Google found the solution, and I stopped panicking: Switch off, pull out the RAM, unplug the modules and plug them back in, push it back in. Reboot.
Of course, if it had still been flashing after that, then I’d definitely start panicking.
By the way, I still love the Mac Pro build, and how easily accessible the components are. I wonder if the new Mac Pro will be as good?