just force it in with a hammer. if that doesnt work get some aluminum foil and wrap it around the bottom then get some paper clips and stick it in the slots on the motherboard.
ok i hope you didnt do that but if you did please send pictures. seirously though, RAM should go in easily. if it doesnt slip right in, try turning it 180 degrees. if it doesnt slip right in, then you have the wrong stuff...its that simple. thats why they have different sockets for different types. but just to make sure, try putting the known good RAM into the slot you are trying to put the new RAM into, just to make sure the slot is OK