Make sure you meet all requirements: .NET Framework 4, DirectX, and Microsoft C++ 2010.
After you have downloaded all the requirements, make sure you have Winrar which is one of the most important programs and everyone should have Winrar. Find an undetected injector from the Crossfire Spammers/Tools/Injectors section. After downloading one, extract it to your desktop.
Then, grab an undetected hack for your CF version. After downloading those, extract the one/two SnDrv files to your desktop. Remember to disable your antivirus as well, since they detect these as viruses, which is fake.
Once you're done with the downloading crap, run your injector as an Admin, browse the SnDrv's from the hack, toggle Auto Inject + Close After Inject and run CF. If the hack requires a msg box, it should pop up. If all is done, you have correctly run a hack.