problem with medion mim2060 1gb ram installation?

hi,i have put a 1gb pc2700 ddr333 sodimm module into my notebook and i find that when i switch the computer on,the hard drive kicks in,the cd/dvd light stays on for about 20 seconds,then nothing. There is just a blank screen,if i add the 256mb card in the computer sometimes it may boot up and system info shows that 1.21gb ram installed,tried changing slots,but the computer boots up every time when 256mb card is installed on it's own.the original 256mb has HYNIX chips on it,so as the 1gb card the only difference apart from memory size,is the 256mb module says that it is pc2700s instead of pc2700 not sure if this is a problem,thanks