just use DDR, not DDR2. I don't think many, if any, laptops use DDR2. go to www.pricewatch.com and look up some memory.. Also, you gotta see what speed your laptop can handle... too much and it won't work at all..
DDR modules are backward compatible with slower DDR modules in 99.99% of PCs, in otherwords you can use PC3200 in a machine that takes PC2100 or PC2700. The reverse is NOT true, PC2700 won't work in a machine needing PC3200. (it might, but the ram will clock down or it maybe unstable, usually the machine won't boot at all)
Some rare motherboards are PICKY, they only want the speed they originally came with. A notable case is the old Intel VX chipset, it HAS to have PC 66 RAM, PC 100 won't work. Another one is the old Gateways with 66MHz FSB PII CPUs, these need PC 66 and won't take PC100. It's been a LONG time since I've seen one of these picky boards.
Currenty, only the Intel platform with the latest chipsets like the Intel 9xx and Nvidia Nforce 4 Intel use DDR2 (VIA and others make a DDR2 chipset too). DDR2 modules are also backwards compatible, DDR2-800 can be used in amachine that uses DD2-533.
DDR modules have 184 pins for desktop modules or 200 for notebook modules, DDR2 has 240 pins. Notebook DDR2 has 200 pins, so check the label. (i'm not sure if they are keyed differently)