Changed CMOS battery on a Dell Optiplex now PC won't power up at all
I've got a Dell Optiplex SX280 that was reporting system voltage low on the CMOS battery.
So ordered a new battery, took out the hard drive very carefully, took out the old battery, put the new one in and reassembled. Found some very helpful online instructions here: Installing Dell Optiplex SX280 Battery - Page 3 - iFixit which I followed.
But now I have no power to the PC at all - nada. Switching it on at the power button does nothing.
I've tried swapping the old battery back and that has the same problem - no power at all now.
Have checked all the obvious things like power cables plugged in at the back of the PC, power cable reconnected to the hard drive etc.
This is the first time I've changed the battery on a motherboard and I can't help thinking I must have overlooked something? Can anyone point me in the right direction?