With help from OWC I upgraded my early 2008 mac book 4,1
From 500GB drive to 1TB Hitachi 7200 RPM SATA 2 drive
Also from 2x1GB to 1 4GB & 1 2TH DDR memory sticks.
Upon start up , start up noise and blank screen.
I ran 8gb from Crucial in my late 2008 unibody for six months and awoke to the sound of 3 loud beeps telling me the memory had failed. Crucial sells the correct memory but does not warranty it, something I failed to notice before purchasing. I have now purchased the 8gb upgrade through OWC, who does warranty the memory. This upgrade made significant improvement, otherwise I would now be shopping for a new Macbook. Other than the inability to function with 4gb, this computer still runs beautifully. I need a new battery but don't really carry this one around anymore.