Close your client, go to C:\Users\"Your user"\RuneMate and remove the *.rm files. Mouse should be alive the next time you launch the client. Important note: To help prevent the dead mouse from occuring, try restarting the client without removing the files, see if that fixes it, then remove the files and try again. Report the results here or report them to @Cloud and/or @Arbiter so they can resolve it. Cheers!