Can you give us your system specs (use Speccy if you don't know them).
Now either you can't run CF normally because your gfx card / something else sucks or you have a program open that overloads your system (could be a virus of some kind too). So if you're sure that your PC could handle CF try gamebooster or smartclose and scan your PC for viruses /
Also try updating directx: Download details: DirectX End-User Runtime Web Installer
And your gfx drivers:
for nvidia: Drivers - Download NVIDIA Drivers
and for ati: Graphics Drivers & Software