i removed emule from my computer using the uninstall option.
but there is still a file in the emule\temp directory that is about 700 MB when i try to remove it manually i get a message that the file is USED by another aplication.
how can i safely remove that file?You can safely remove the temp files by booting into safe mode, this make sure that no other programs are using it causing the lock.

Since you have uninstalled emule and you no LONGER plan to re-install therefore there is no reason to keep it.  You are giving that option if you later re-install emule, the temp files contains all the parts completed or not completed down loads from the net. if you did re-install, emule resummes with the temp files so you don't have to start from scratch again.

If you still have PROBLEMS in deleting the temp files, re-install emule and select Tools-Open incoming folder and delete all the files.  Now in the main interface select "shared files" and click on reload, this clears any memories of the files marked as shared, by default emule automatically SHARE all files from the incoming folder.
HTH