If you have two (2) pieces of memory installed sa memory bank, try installing only one (1). then check mo.
Pag ayaw, ilipat mo yung same memory don sa kabilang slot..

If di pa din gumana, use the other memory naman (same procedures as above).

But again, before mo yan gawin, make sure to clean first the memory (yung gold tip; kaskasin mo ng eraser).