Re: how to know which ram to buy
Your best bet would to look at the ram stick, take it out channce are it'll have the key information on the stick, and write it down, and then you need to simply go to a site and order the same type and IT SHOULD WORK. We need detialed specs to tell you for sure it'll work.
Main Rig: I7 920 CPU, 6 Gigs ram 5870 GPU
M17X Laptop 2.8 Ghz Dual Core, 4870 Radeon