Desktop icons have disappeared
My Mac HD and backup drive icons have disappeared from my desktop. It all started when I tried to save two .m4a files to the dekstop. For some unknown reason they were invisible. I googled for help and found a link that told me to delete the com.applefinder.plist from Library Preferences and select relaunch in the Finder. After doing this not only could I not see the m4a files - but my HD and backup drive icons were now invisible.
Please advise how to restore these icons and find my m4a files. Thank you.
Mac OS X (10.6.8)