Memory Management is about the of managing of computer memory. In its simpler forms, this involves providing ways to allocate portions of memory to programs at their request, and freeing it for reuse when no longer needed.
So your first "port of call" should be to check each memory stick by taking one out at a time to see if this solves the problem.
If you have upgraded or replaced the original memory, try putting back the previous sticks if you still have them.