I also could not find recovery manager, and I also did not have the option when going to device manager and selecting action to scan for hardware changes. However, I fixed the problem by these steps:
1) Go to device manager
2) Select sound, video, and game controllers from the list, and select high definition audio device when it drops down
3)New window opens. Select the driver tab. Click uninstall.
4)Then after it is uninstalled, go back to device manager window.
Select action, and THEN you will have the option of scanning for hardware changes.
Select this option and it will reinstall and the problem should be fixed.
(I have an acer laptop with windows vista but I thought these steps could be useful for others as well)