Memory Upgrade Problem

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.

It did turn out to be a bios update that was needed, so I have it up and running. Thanks for trying to help. Computers though - now my laptop I use for work that is just over a year old has a hard drive failing - so guess what I have to do this weekend - UGH. Thanks again.

Ringil, here's the link to Toshiba's site.
http://www.csd.toshiba.com/cgi-bin [...] ily=804517

They show a BIOS ver. 1.4 available.
http://askiris.toshiba.com/Toshiba [...] 2091904460

In addition, when I was searching for the correct download/spec page, I was here and found links to 4 total BIOS updates. Whenever considering a BIOS update, I would recommend getting ALL of them, in case your chosen one doesn't work right.
http://www.csd.toshiba.com/cgi-bin [...] 3&x=0&y=0#

Also, I'd be sure to download everything for your computer that you find there, create a special folder for it. Save the support bullitens, the specs, etc.. Never can tell when they'll trim off some pages or info - like they removed the links to the earlier versions of the BIOS from the main download page.