I just got this off steam, waited for the download which took forever and now it wont start, the detection.exe said my Processor was not a dual core incorrectly and the game is refusing to start up, it gives me the "Needs to Shut down" error every time. I have a dual core because I run CoD5 which requires a dual core as do most of my other games which I run just fine. I don't know why this isn't working.

System:
Windows XP
Media Center Edition
Version 2002
SP 3

Computer
Intel(R)
Pentium(R) D CPU 3.00 GHz 2.99 GHz
2.00 GB of RAM

Display Adapter
NVIDIA GeForce 7800 GTX

if you want help post a dxdiag.

Well, Steam just randomly started updating the game about ten minutes ago, I'll see if it works after the update if not I'll post one.