zuala ehy have u made 3 topics? for hte same question??
the problem is maybe dust/dirty in the slots in wich you but the ram
just take them out adn clean the ram and slot..also be caeful not to discharge you statis to it..wich may blow 1 of the ram modules.
to test the ram..try putting 1 chip at a time in different slots to c if it fails.
let me know wat happened.
also specify the make of ram and mobo/cpu