Laptops aren't standardized like pc's are. Between all the different manufacturers, and at the rate technology moves, there's probably hundreds of kinds of laptop memory out there.
What's the make and model of the computer? Maybe I can do a search and figure out what you need. I can at least give it a shot.
The last time I was working on a laptop for somebody, I coudln't figure out the problem for sure, but kinda figured it was between the motherboard, cpu, and memory. I looked around ebay, and found the same computer that had a broken screen, but still booted up normally. So we bought that for about $90, swapped internal parts, so his laptop is working good, and he's got a bunch of extra parts in case something else on his would break like the cd drive or keyboard.
Back in high school I used to buy laptops for dirt cheap on ebay that had broken power connectors, fix them for less than 5 dollars, and then sell them for 4 times what I bought them for. With the spare time I have lately, I should get back into doing that again.