Optiplex 7010 diagnostic LED

so there are more than two kinds of code when PC is no POST.  I encountered either the 3-2 or 2-3.   I do not remember exactly.  ram was 4GB PC3-12800U which should work.  the code table says either No RAM or Bad Video chip.  that is just machine talk.  you should not read too much in it.   The only thing that points in about right direction is memory related issue.  Note it is not so simple to tell 3-2 from 2-3 code as you need to tell which has a longer pause vs shorted pause.

  The actual problem is either ram was not seated well, or bios is not comfortable with 4G.  Note that if you actually took out all ram, the pc would Beep.  so it does beep in rare occasion when it senses no memory at all.  I also did replace cmos battery w new one and cleared cmos to no avail in the beginning.  what I discovered is that the old bios needs a bit coaxing, like a scared little kitten needs a small treat first.  so I used a small 2GB PC3-10600U,  smaller ram and lower speed.  then PC POSTed.  after that inital memory priming, I then went ahead with the 4 GB 12800 which worked.  such things were never written in Dell or other text book on pc, but only come from hand on trial and error anecdotes.