Well, it is a 32-bit computer so, assuming a 32-bit address space, it should be able to address 4GB memory.
http://ark.intel.com/products/36331/Intel-Atom-Processor-N270-512K-Cache-1_60-GHz-533-MHz-FSB Intel® Atom™ Processor N270 (512K Cache, 1.60 GHz, 533 MHz FSB) Product Specifications
But, this could be limited by the chipset and motherboard. Provide that information for further confirmation.
In most similar computer system configurations, the BIOS will reserve a portion of the address space for the BIOS itself to use and for things like device address, graphics buffers, etc. Typically, only about 3.25GB of the 4GB address space will be available for general use (or less if you, within the BIOS, reserve more for graphics).
SVALPASSOS, just like mentioned before this could be limited by the your chipset model and motherboard model. So, please provide this information in order help you.
Thanks Doc and Scott.
According to your request I have the information you need to help me.
KBC Version 02.08
Intel 82801GHM (ICH7-M/U)
Even though your processor is 32-bit, your memory is limited to 2GB by your chipset:
http://ark.intel.com/products/36549/Intel-82945GSE-Graphics-and-Memory-Controller Intel® 82945GSE Graphics and Memory Controller Product Specifications