Ah, wait:
Portal 2 Minimum System Requirements:
CPU - 1.7 GHz Processor: Check
RAM - 512MB: Check
Video Card - DirectX® 8.1 level Graphics Card (Requires support for SSE): Not check
Windows® 7 (32/64-bit)/Vista/XP: Check
Other - Mouse, Keyboard, Internet Connection: Duh, check XD
So all I need is that card... what are those things, anyway?