I got a Toshiba satellite a105-s100 laptop. It has 2 memory cards in it right now. Both 256. I bought 2 2gig cards and put them in. When I start the laptop the power button lights up I hear the hard drive start then three little lights around the keyboard light up. It does this three times and then does nothing. I've taken them out and put them back in several times. I know I put them in right. Anyways I took them back and got two 1gig's thinking it was too much memory. Put them in and same thing. My computer says it's pc2-4200, ddr2, sodimm. every thing seems to mach. When I put the old cards back in it works fine. any suggestion would be greatly appreciated

some laptops are maxed out on memory when they come from the factory. i had a sony Vaio that had the same problem. it came with 2, 256 sticks of Ram and i replaced it with 2 X 512 and it wouldn't even turn on. i called sony and they said that the max memory was 512. so your motherboard probably won't support more that it was shipped with. they do that to cut back on cost and so you have to buy a new one in 2 years

I believe that the Toshiba satellite a105-s100 will only take a max memory of 1 GB DDR2 667. You will need two 512meg cards.

Well the manual says that it can take up to 2048mb, however you can only use 2 chips of 512mb, which however you count doesn't add up to 2048mb..Anyway, most likely the max is only 1 gig, so you'll probably have to get 2x512mb :)