Precision 7810 2 amber blinks fallow by 7 amber blinks

Hello,

My precision 7810 during start up 2 blinks followed by a short pause, 7 blinks, long pause and repeats. According to Dell web site this is: memory modules were detected but a memory failure has occurred.

The system only has one memory module, this computer is out of warranty.

I have tried the following:

Resetting the memory, as well putting in the other memory slot

Replacing the memory, with a known good memory

At this point only option I can think of is replacing the motherboard, I am hoping there may be other ideas I miss before I do this.

Thanks for the help.