Hello, First I want to apologize for this lengthy post. I just want to be sure I'm relaying all the relevant information I can think of. ---- I am running into an odd problem, and thought I'd ask if I'm overlooking something. I recently bought a 512MB sodimm for my powerbook. Now in the past when I've added memory to x86 machines (and I've done it a lot), it's usually just a matter of putting in the new dimm and powering the machine on - the BIOS sees the new memory and registers it. On older machines I remember having to go into the BIOS and manually enter the memory size. I have never ever had a problem with bad memory. But anyway - so I get this pc2700 sodimm from Crucial, put it in, and turn the machine on. It boots up to the start of the graphical interface, but freezes on a clear blue screen. I power down, boot it back up, and it boots... but freezes during login. So I try just this new chip, and run into problems; so I put in just the original 512 and things are fine. Okay. Bad RAM. I send it back to Crucial, and they send me a replacement. So today I put in the replacement, and run into EXACTLY THE SAME PROBLEMS. Both sodimms in, things eventually freeze. Just the new sodimm in (sitting in the socket that the apple sodimm normally sits in), and it freezes during bootup. So I put the original sodimm back in by itself... and everything is good again. Now I've never had trouble with Crucial memory before (in PCs). The sodimm says "PC2700S", which is exactly what the factory installed sodimm says. It just seems odd that I'd get two bad sticks of RAM from them. So: Is there some obvious step I am missing? Something I'm supposed to manually reset once I've added the RAM? Thanks for any insight you can provide. Edit: My powerbook is one of the new 15" 1.25GHz powerbooks, which came with one 512MB stick of RAM installed.