http://www.gamesas.com/index.php?/topic/1142151-rel-mtes4-manager/page__hl__mtes4, an awesome little app that lets you create cloned copies of your Oblivion install.
Before you do that, do yourself a favour and uninstall Oblivion from your Program Files folder. Oblivion and Windows 7 UAC do not get along. Make a C:\Games folder (or something) to install to.
Make sure when you uninstall to delete the User Name\App Data\Local\Oblivion folder and the User Name\My Documents\My Games\Oblivion folder. If you want to save all your current game info then BACK THESE FOLDERS UP first, then copy them back over after you reinstall.