If you are thinking about getting the new Windows 7 that will be out by the end of the year you might want to know the minimum requirements:
• 1 GHz processor (32- or 64-bit)
• 1 GB of RAM (32-bit); 2 GB of RAM (64-bit)
• 16 GB of available disk space (32-bit); 20 GB of available disk space (64-bit)
• DirectX 9 graphics device with WDDM 1.0 or higher driver
Seems kinda low to me. I would recommend a 2 gig processor at least, and 2 gigs of ram. Thats why they call it minimum requirements.