Fix your audio drivers. Hardware problems can be caused by outdated or malfunctioning drivers. Make sure your audio driver is up to date and update it if needed. If that doesn't work, try uninstalling the audio driver (it will reinstall automatically).

The Program Install and Uninstall troubleshooter helps you automatically repair issues when you're blocked from installing or removing programs. It also fixes corrupted registry keys. First, you'll need to download the troubleshooter. Download troubleshooter.

Lock or unlock specific areas of a protected worksheet. You can insert a drop-down list of valid entries (also called a drop-down menu or drop-down box) in Excel to make data entry easier, or to limit entries to certain items that you define.