I recently bought 2x256MB SDRAM SODIMM modules (unbuffered, non-ECC) to replace my existing 2x64MB modules in my Dell Inspiron 4000 laptop. However, the computer doesn't even start at all! Is there any way of running a diagnostic on the computer? On the modules? I even tried plugging them in one at a time, switching sockets for each one. What's my best option? By the way, I do have the latest BIOS installed (A23).