hi, i've put 2 sticks of 1gb ram in my laptop (max capacity 4gb) and it won't boot up, it goes to a screen offering safe mode, safe mode with prompts etc etc. whatever i choose it goes back to the same screen. i put one of my old 512mb sticks in with a 1gb and the computer boots to the aforementioned screen, i pick last known configuration and the pc goes into checking disk:c. when its complete it boots up. why won't it boot up with 2 1gb sticks in? why does it go to check disk when i put the 1gb and 512 mb sticks in?