I have a Toshiba Qosmio G25-AV513 running Windows XP. This computer originally has two 512 mb memory chips. The specs says it will accept two 1 gig memory chips ddr2. I purchased Crucial's memory and verified compatibility and the computer would not boot up. I got the memory replaced in case it was defective and still no go. I then went to Toshiba and purchased the Kingston memory they said was compatible. Still no go. Toshiba will not offer any help since there is no warranty on the computer - even though this is a simple memory upgrade. What is even more strange is even the origianl memory has to be put back in the correct order - if you reverse the two chips it will not work. Does anyone have any ideas why this laptop is having this memory issue. Thanks in advance for any help or suggestions.