Hmm could be locked... Ok try this:
1) leave only Samsung RAM in your laptop, remove other module. Start the laptop see if it works.
2) Now remove Samsung RAM and, this is important, stick your other module in the SAME ram slot where samsung ram was and start the laptop, see if it works properly
3) Repeat steps 1 and 2 but using ram slot that was UNUSED
4) report back with results
PS: you can leave laptop plastic where ram is open so you don't have to screw it off and on all the time while testing this