OK, well the problem has been resolved by replacement of the m/b.Still none the wiser as to the root cause of the the problem. As an aside, the new m/b arrived without a ServiceTag code configured and the tech assigned the original code although the m/b would have a different serial number. If the BIOS detects that no ServiceTag is set then a dialog is displayed to allow this to be set at first boot... presumably a one shot process.
Hi, we have had an Inspiron 5400 AIO running (Win 10) for a few months without problems and it has developed a boot problem.When it is powered up a Dell Security Manager message appears stating that I need to enter the system or administrator system to access the system. We spoke to Dell Support who provided us with what should be the correct password for this system but it was deemed invalid. Yes we have verified the correct password multiple times with the service agent but we just ended up getting invalid password errors and subsequent shutdowns. We have been told that it will require a motherboard replaced which is being organised but I am surprised that there isn't some other solution. Resetting of the NVRAM requires the password.I presume the SSD and HDD will be moved across so no potential data loss.We are long term Dell users with a couple of Inspiron desktops still running strong so are happy customers but this issue doesn't inspire confidence. I do wonder what has caused this catastrophic issue.
Inspiron 5400 AIO BIOS system/administrator password invalid