Some time ago, I bought my wife a used C400 with 512mb of ram. I was thinking of upgrading this if possible and came across a few websites that say the maximum capacity is 1gb in two slots.
I only see one slot under the door in the bottom - so my question is - where is the other slot? I checked the online manual, but there is no reference to another slot in the C400.
Generally, when only one memory slot is accessible, the other is on top of the mainboard, under the keyboard.
I actually just found an old Dell tech web page with photo instructions for disassembly of the C400 and it does indeed show a ram module below the keyboard.
Not sure it's worth messing with at this point as the hinges are on the way out too. If I can find a pair of 512 sticks cheap I may give it a try.