Have you tried removing the new RAM to see if that may be the cause of this problem? Intermittent RAM problems can cause this sort of behavior, especially since laptops don't have ECC (error-correction) memory. If it has an occasional glitch, then this sort of behavior is not unreasonable to expect.
rubberman
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This is Windows 7? When the screen goes black, any error information on the screen? I would also suggest removing the RAM you installed. An error in memory would be the cause of a BSOD.
JorgeM
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