It's quite possible the two larger sticks of RAM "broke the camel's back" and the power supply died. My next stop would be the repair shop.
Hope this helps.
I have a Sony Vaio S460 laptop.
Recently it had been lagging really bad, and so I was advised that it might be a power supply problem, or, another solution would be to upgrade the memory.
I went to my local computer store asking about it, and he recommended trying to upgrade the memory (I currently had two 256 MB memory sticks, for a total of 512). I told him my model number, and he pointed me to a Kingston 1 GB memory stick, and said he was pretty sure that it would be compatible. Since it was only $10, I bought two of them.
Ok, so I went ahead and replaced the two 256 MB memory sticks with my newly acquired 1 GB memory sticks. But after I put the laptop back together, and I pushed the power button, nothing showed up on the screen (although the lights indicated the power was at least on).
I went back and replaced one of the 1 GB with a 256 MB, but now in addition to the blank screen, it wasn't even showing the light that power was on!
At that point, I went ahead and put the other 256 MB stick in (so this would be how it was before I upgraded), and again, it wouldn't even turn on!
I took out the memory stick from inside the computer, and tried to have the computer turn on with just the 256 MB in the other slot, no luck. I tried to turn it on with the 1 GB in the other slot (and again, leaving the other slot empty), and still, no power!
What's going on?!?! I really hope it isn't something major, but I don't understand how it could be considering all I did was swap out the memory sticks, and even then, I went back to how it was and still no power.