Windows 7 System Requirements

Source from Microsoft..

Requirement that need to run Windows 7 on yr PC..

Ram
1GB for 32-bit (x86)
2GB for 64-bit (x64)

Processor
1 Gigahertz or faster 32-bit (x86)
1 Gigahertz or faster 64-bit (x64)

Hard disk
16GB for 32-bit (x86)
20GB for 64-bit (x64)

Direct X
Direct X 9 graphic device with WDDM 1.0 or higher driver