Keep the ram and buy a new motherboard...
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OK, you need pc133 or pc100 ram, which has 168 pins and 2 notches...
You bought some ddr ram (likely pc2100, which is 133x2)that has 184 pins and 1 notch...
PC133 ram is getting to be expensive... so, really, keep the ram and get a cheap $50 board or something... that may not be the best advice, but not knowing anything about your computer, it is hard to advise anyone to spend money on pc133 ram...
<font color=red><b>To reign is worth ambition though in Hell:
Better to reign in Hell, than serve in Heav'n.</b></font color=red>
John Milton, <i>Paradise Lost</i>, II 262-263