No interim adapters, switches, extension cables etc. between the headphones and PC - correct?
Does the static ever stop at all? Any patterns to the static's occurrences? E.g., when conditions are warmer and more humid versus cold and dry. May be some static discharge. Do your ears ever get shocked? Especially while putting the headphones on or off?
If the headphones work elsewhere and different headphones have the same problem on your PC then the problem is indeed likely to be your computer.
Power off and open the computer case.
Check all audio related connections, cables, and cards. Be sure that all are fully and securely in place.
Look for anything else that may be loose, not fully seated, wires out of place.