Hoodibaba the link that skidzy gave is good, you don't just need PC2700 DDR SDRAM you may also need memory with the same latency, its not important to know what this is but it is important to get memory that you're motherboard will be able to use. Crucial guarantee their memory will work.
Use the Crucial Memory Tool as recommended by Fingees. Even if you don't buy Crucial brand you need to buy EXACTLY the same spec. So if it says DDR2700 DDR333 CL2.5 etc buy EXACTLY that. Otherwise you might have problems.
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