I just intalled a 2gb stick and I know I did it right but it just sits in black screen
But mines does boot with a 2GB stick (right now) and people said they've been able it get 4GB with 2x2GB sticks.Edit: WAIT! You have a Core Duo MacBook? Not a Core 2 Duo? Then, NO, it wont work at all. Those machines have a 2GB maximum RAM limit. 1GB per slot. I've read that they wont even boot with a 2GB DIMM (let alone two) in the machine.
I just intalled a 2gb stick and I know I did it right but it just sits in black screen
You really need to push the RAM in right. If you press really, really hard, then you still have two millimetres to go. Typical sign for a MacBook is that the L-shaped bit of metal around the battery is a bit difficult to get in because the RAM isn't pressed in deep enough.
If it is the Macbook in your sig, that is a Core Duo 2.0 Rev. A, they will support up to 2gb, ( 2x1 gb chips), so your 2GB chip will probably not work in it.
If you have a core duo, then 2GB is the max and likely to be your problem.
Yeah, NOW people are telling me that...Ram works better in pairs and seems to me you're pushing your machine with that 2GB stick. I'd go with 2x1GB sticks. But that's me.