You need to check if your computer answers to the minimum system requirements for Project Powder:
OS: Windows XP / Windows Vista
RAM: 512 MB
HDD: 1GB Free
CPU: 1.6 GHz
Graphics Card: Geforce 4 mx 440 / ATI Radeon 8500 or equivalent
DirectX: DirectX 9.0c or higher
If this requirements are fulfilled try to reinstall the game.