immediate help on whether i need to upgrage my bios for my dimension 2400 pc. 

I've bought 2 512mb rams to upgrade my 215mb ram; one of them is 512mb ddr 266mhz cl2 pc2100U Nanya, the other is 512mb ddr pc2700U cl2.5 Samsung.  I tried one by one, the Nanya one couldn't even restart my pc, and the Samsung one once a while pops up an error window and sometimes gives me a blue face.  Heeeeeeeeeelp, do I need to upgrade bios in order to use my 2 512mb rams??? T_T