I get notices from Dell indicating that I need to update the BIOS of my OptiPlex 990, but when I follow the link to download and install, I'm told that I must first install AO5 in order to proceed.  After downloading and attempting to install AO5, I'm next told the I must "configure Windows to allow flashing".  A quick search regarding that issue leads to instructions for editing the registry, but the key that I'm told to delete doesn't exist.

Is there a solution to this mystery, or am I to just ignore the continuing update notices?

Any assistance with this issue will be appreciated.