Reply #3: Here ya go:

[Occulus]

PC System Requirements
OS: Windows 7 / Vista / XP
Processor: 3.0 GHz P4, Dual Core 2.0 (or higher) or AMD64X2 (or higher)
Memory: 1GB XP / 2GB Vista
Hard Disk Space: At least 7.6 GB of Space
Video: Video card must be 128 MB or more and should be a DirectX 9-compatible with support for Pixel Shader 2.0b (ATI Radeon X800 or higher / NVIDIA GeForce 7600 or higher / Intel HD Graphics 2000 or higher).
Audio: DirectX 9.0c compatible

Here are the requirements for the first Portal:

PC System Requirements
Minimum: 1.7 GHz Processor, 512MB RAM, DirectX® 8.1 level Graphics Card (Requires support for SSE), Windows® 7 (32/64-bit)/Vista/XP, Mouse, Keyboard, Internet Connection

Recommended: Pentium 4 processor (3.0GHz, or better), 1GB RAM, DirectX® 9 level Graphics Card, Windows® 7 (32/64-bit)/Vista/XP, Mouse, Keyboard, Internet Connection

If you'd like to see if your laptop can run Portal 2, I recommend downloading Alien Swarm (which is free), as that game apparently uses the same version of the Source engine as Portal 2. If you can run Alien Swarm, even with everything in the video options turned down all the way, you should be able to run Portal 2.

The original Portal was free last year as part of some promotion or other, and is now $10 on Steam.