Minimum Requirements to run Unreal Tournament 2004:
Windows 2000/XP – It works just fine in Vista, too
Pentium III 1.0 GHz or AMD Athlon 1.0 GHz or faster (Pentium® or AMD 1.2GHz or greater recommended)
128MB RAM (256MB RAM or greater recommended)
32 MB video card required (64 MB NVIDIA or ATI hardware T&L card recommended) with DirectX 9.0b
Windows-compatible sound card