Idk the officla min and max but

My lowest pc that can run it is.

5 Years old
windows xp
2 gb ram
2.1 duo core processor
nvidia 6100 gs graphics card

My highest running pc is a 1 year old laptop
Runs everything on max except res and AA

nvidia 9800gts
4gb ram
2.2 duo core
windows 7

These are the System Requirements for final version of C&C 4:

==================================================================
System Requirements
==================================================================

Command & Conquer 4 Tiberian Twilight requires DirectX 9.0c. You
can install DirectX 9.0c by following the onscreen prompts during
the game's installation process.

MINIMUM SYSTEM SPECIFICATIONS:

Required- Internet connection required to install and play.
OS - Windows XP SP3 / Vista SP1 / Windows 7
Processor Intel Core 2 or better / AMD 64 X2 or better
Memory 1 GB for XP / 1.5 GB for Vista and Windows 7
Hard Drive At least 10 GB of free space
DVD-ROM - 8x Speed
Video Card 256MB RAM with support for shader model 3*
Sound Card - Direct X 9.0c compatible
DirectX - Version 9.0c (included)
Online - 2 10 Players
Input - Keyboard, Mouse, VOIP headset

*Supported video cards: Nvidia GeForce 6800 or better, ATI Radeon
X1600 or better. Laptop versions of these chipsets may work but are
not supported. Updates to your video and sound card drivers may be
required.

Note: While you will be able to play Command & Conquer 4 Tiberian
Twilight with the specifications above, play experience may improve
if you have additional RAM above the requirement. Please refer
to the section on Optimizing Graphical Performance in this ReadMe
file for more information.

I have Windows XP SP2. Can I install the game???