I'm using x64 so I can't test but it should look like this for W7 if the patchpae2.exe is in \system32:
C:\Windows\system32>PatchPae2.exe -type kernel -o ntkrnlpx.exe ntkrnlpa.exe
You can try right-click & pasting the above line (the bit after '>') into your cmd box.
C:\Windows\system32> =
path to filePatchPae2.exe =
file-type kernel -o =
switches (what the exe must do) must be -[switch] ie no space between - & switch
ntkrnlpx.exe ntkrnlpa.exe =
target(s) - these are the things to be changed
That will be the format for each instruction.
ensure you have no typos, no extra spaces, that the "-" is in place etc
make sure it is an admin rghts cmd box. It will say 'administrator' on the top bar
make sure your AV allows it to run - it will access core OS files so most AV will think it is suspect.