Exchange 2003 C Drive Filling up – MMC gone :(

hey guys, long time reader first time poster.
I have an exchange server that is filling up C Drive and I have no idea how to check what is happening.
All logs etc go to another partition, i managed to move all of the $uninstall hidden files (search function as the view Show Hidden files and folders won’t work either). I managed to get 900mb of space back and within an hr I had 19mb left again.
Any help would be appreciated.
Thanks
David