Memory Problems

Recently my PC seems to be having memory problems whenever I access AOL. I’m running 256 MB of RAM, but am showing a high % of system resources being used. I ran the Norton Utilities 2001 software to check my memory and it showed an error. I replaced the 256 MB with a new one and received the same error. I replaced that with the original 96 MB sticks that were initially in the computer. The memory tested out OK, but AOL 5.0 still crashes after a few minutes. Any ideas ?