How to solve the invalid DOS command in the Win7 command prompt environment?

Fault phenomenon: I don't know what happened in the past few days. After entering the command prompt state, my windows7 prompts no matter what dos command is executed: “** is not an internal or external command, nor is it a runnable program or batch. Process the file. ” Is this phenomenon poisoned?
Solution: Not poisoned, but some software modified the value of path.
You can try this operation: right click on my computer → attribute → advanced system settings → environment variables, see what is inside the path value? For example, some software will be changed to c: PRogramfiles (x86) stormiicodec ;c:programfiles(x86)stormii, also removes the real system file address.
Now you add %systemroot%system32;%systemroot% to the value of path; this will solve the problem.