How many DIMM slots do you have?
The specs on gateway say you only have 2, and it says it comes with 2 512 sticks already? Is this correct.. or am I reading it wrong?
Did it come with one 1024 stick?
or are there more then 2 dimm(ram) slots?
How many dimm slots do you have, and are there different colored slots?
or did you link to the wrong computer?
Also, do you simply just get a black screen, or do you get the black screen with the white font?
does it do the memory test?
Verify that the ram you got is actually the ram you bought, check the specs on the sticker on the ram.
It could possibly be a bad ram slot...
Try using a different one.. also if you currently have 2 sticks and are adding 1 more.. the current 2 sticks could be running in dual channel mode. If you only have 1 stick in there.. and 4 slots.. and they are color coded.. (ie 2 red, and 2 blue)..
try putting both sticks in a blue slot.. if that doesnt work.. try putting 1 in blue and 1 in red .. depending on the manufacturer of the motherboard, they follow different rules for using dual channel ram.
What OS are you running?
Go to RUN-> msconfig -> Boot (boot.ini on xp) -> Advanced options ->
is /MAXMEM checked? if it is.. uncheck it .. now see if it works