RAM Memory Upgrade - from 1GB to 4GB for less than $100 at NewEgg

The Toshiba Satellite A215-S7422 comes with 1GB of memory (RAM). This is barely sufficient for running Microsoft Windows Vista. The specs state that this laptop is upgradeable to 4GB of RAM. So, I found the best deal at www.newegg.com; a 2GB Corsair module for $35 after rebate. I bought 2 and now have 4GB of memory. However, beware, only about 3.5 GB is recognized.