Once, I also installed perl on a system without admin rights. So the PATH environment variable was not updated, and it made perl hard to use. But I created a shortcut to cmd.exe and set Target to:

%SystemRoot%\system32\cmd.exe /v:on /k set path=c:\perl\site\bin;c:\pe
+rl\bin;!path!
[download]

So the PATH is set correctly whenever I use the shortcut to spawn a cmd shell.

I also had to update a few other things, like the PATH in Vim, and the path to perl in the pl2bat program that comes with ActiveState.