Dell Inspiron 2600 Memory Confusion

[owensdj]

I helped someone add 256MB of memory to their new Dell Inspiron 2600 notebook. They ordered it with 128MB of memory and then bought a 256MB 144-pin SODIMM from Crucial.com. I thought I could add the 256MB of memory to the existing 128MB because Crucial's info on the Inspiron 2600 seemed to say I could, but the manual only talked about replacing the one memory module. I took out the existing SODIMM and replaced it with the 256MB SODIMM from Crucial. The notebook had a total of 320MB after I turned it back on. Sounds like there must have been 128MB of built-in memory minus 64MB for the shared video. How much memory was in the SODIMM I took out? Can anybody with an Inspiron 2600 clear up the memory confusion for me? Thanks.