dir [filename] /s [for all subfolders]
from wanderer is what you need, then you're finding files.
To get a set of commands to act on the list of files found, you need something like:
dir filename.ext /s/b>fileLIST
for /f "tokens=*" %%F in (fileLIST) do WHATEVER %%F
where WHATEVER is your command.
If at first you don't succeed, you're about average.