Did you rename exiftool to remove the
(-k)? Are you sure you set the PATH env variable properly?
If you renamed the file and still can't run it from a new command line (command lines created before changing the PATH will still have the old PATH), then the PATH wasn't set.
Open a CMD prompt
Type
sysdm.cplSelect "Advanced tab"
Hit the "Environment Variables" button
You should end up with this

Find the PATH entry under "System Variables"
Click Edit
When the new window opens up, click "New"
Click Browse and find the directory exiftool is in
Click OK for all the windows
After that, when you open up a new command line, exiftool should be available.