Question : Problem: Having trouble adding additional memory to HP Pavillon a6000n running Vista Home Premium

I'm trying to add an additional 2GB of RAM to an HP Pavillon a6000n running Vista Home Premium.  The computer won't boot, however, with more than 1GB installed.

I can boot the computer into safe mode with 3GB installed but when I try normal mode, the computer runs the Vista green blocks boot screen for a while and then the screen goes black.

Is there an obvious Vista startup process that doesn't like more than 1GB of RAM?

Answer : Problem: Having trouble adding additional memory to HP Pavillon a6000n running Vista Home Premium

slot 1 512MB
slot 2 1GB
slot 3 512MB
slot 4 1GB?