Question: I don’t know what’s going on these days. After my Windows 7 enters the command prompt state, no matter what DOS command I execute, it prompts: “** is not an internal or external command, nor is it an operable program or batch file. "Is this phenomenon poisoning?
Answer: It's not poisoning, but some software has modified the value of PATH.
You try this: right-click My Computer → Properties → Advanced System Settings → Environment Variables and see what is in the PATH value? For example, some software will change it to C:PRogram Files (x86)StormIICodec;C:Program Files (x86)StormII, and delete the real system file address.
Now you add %SystemRoot%System32;%SystemRoot% to the value of PATH; this will solve the problem.