1 and 3 error in 780 series

I am unable to edit the topic so am posting full details here.

Their are 2 RAMS of 4 GB each one has got problem 6 months back showed  1 and 3 error and I was using the remaining RAM.

Now again the problem came with 1 and 3 and 2 ,4 error for the another RAM.

I have tried most solutions by replacing CMOS battery and so on, nothing worked.

Could somebody tell me where does the problem happening?

It doesnt have service.

Is their anyone to help a little 

Hi there, have you check already the links below about OptiPlex Beep Codes and Optiplex Error Messages?, there is another similar thread resolved link below

https://www.dell.com/community/Optiplex-Desktops/Optiplex-780-amber-light-blinking-1-and-3-amber-power-light/td-p/7785201

https://www.dell.com/support/kbdoc/en-uk/000126021/a-reference-guide-to-the-dell-optiplex-diagnostic-indicators#2005_to_2009

https://www.dell.com/support/kbdoc/en-uk/000124830/dell-optiplex-and-vostro-beep-codes-and-error-messages