The common suggestion on the internet for that problem is to remove all but one mem card.
On desktops the card has to be in the slot closest to the CPU. Try one card , and if the problem persists or changes try the other.
that is a very good suggestion (among other options also mentioned)
sometimes re-seating your memory solves problems but if you have more than one, take them out one at a time to see if one of them is bad (it would do this behavior)
on a PC (desktop) pull out and re-seat all the boards that you can - it is surprising how often this works
clean off the contacts gently