Adding memory and have a ?

[pgwatson4]

I have a late 2008 2.4 mhz 15 inch MBPro with 2 gb of ram (1+1). I have one recently purchased 2 gb ram chip to replace one of the 1 gb chips so I will have 3 gb of ram (1+2). The MBPro will not start with the 1+2 in. Do I need two 2 gb chips for the new chip to work?

 

[m85476585]

It should work with unmatched RAM. Make sure they are both compatible speeds, timings, and voltages. You can try switching which slot the larger module is in since that helps some times. It is possible that the new one is defective, in which case you can try to exchange it.