New 1GB Module DDR2 PC2-5300 667MHz RAM Memory for Dell Dimension C521 at Amazon.com
4GB (1GBx4) Team High Performance Memory RAM Upgrade For Dell Dimension 9200 9200C C521 5100C Desktop. The Memory Kit comes with Life Time Warranty. at Amazon.com
Dimension C521 Service Manual
Dell Dimension 5150 MT Intel Pentium 4 3.06GHz 2GB RAM No HDD No OS BA