Are you running the latest version of WordPress (3.3.2)?
Have you tried deactivating all plugins and activating either the default Twentyten/Twentyeleven themes? If not, try doing that and let us know if you are still having issues and report back here.
If you try this and no longer have the issue, it is a good indication that either a plugin you have activated or a theme you are using is causing the icons to disappear.
I am running 3.3.2 I have tried deactivating plugins and installing Twenty Ten and Twenty Eleven. No change! I am soooo new to this, but I learn quickly.
Do you remember if you had recently installed any new plugins or possibly installed/activated a new theme?
You might want to try backing up your data and doing a reinstall by visiting Dashboard->Updates in the admin area of your site in case a file was corrupted somehow.
