lenovo x61s unsuccessful ram upgrade

[erikoking]

i just bought two elpida 2gb 2rx8 pc2-6400s-666 ram modules, and then i installed them on my thinkpad x61s 7666 running windows 7 ultimate 64 bits. 

the windows starts fine and,  its just suddenly  a blue screen pops up saying there is an error.

so the question are_

what is really wrong with the pc?

are the correct type of ram the ones that i am using? 

how can i fix it?

thank you very much

[richk]

You could have a DOA RAM module. If you havve some sort of memory tester, try the 2 chips one at as time. Memtest86+ is free and good.

[lead_org Microsoft MVP Contributor]

sometimes the 800 mhz ram doesn't work properly in ThinkPads, it is best that you use 667 mhz ram instead.