Reseating the RAM fixed the booting problem. The BIOS may or may not recognize the full 4GB of RAM. Since the OS is 32-bit, it can only address 4GB of memory space, including the graphics card, and all the peripheral devices, i.e. everything on the motherboard (IDE, SATA, USB) and everything that connects to it. Some BIOS's will reserve space for the peripheral devices. Only way around this is to look for BIOS setting Remap Memory Hole. Set to enable. It's possible Dell has a BIOS update to resolve this.