My Dell Vostro 1500 running Windows XP SP3. I found this as an office was clearing out their office supplies. I plan to install SP4 on it at a later date :
4GB kit (2GBx2) Upgrade for a Dell Vostro 1500 System (DDR2 PC2-6400, NON-ECC, ) | eBay
A-Tech 4GB (2 x 2GB) RAM for DELL VOSTRO 1500 | DDR2 667MHz SODIMM PC2-5300 200-Pin Non-ECC Memory Upgrade Kit at Amazon.com