I'm assuming that you're using Windows 7 SP1 or WIN 8/8.1? Go into IE menu, and click
Help>About Internet Explorer.
What does the popup say? IE10 or 11? You can't reinstall IE10 without first uninstalling IE11.
The issues you describe do not necessarily indicate there are problems with your core IE11 install requiring a complete reinstall. Could be caused by a build up of old cache files, or problems with browser extensions, addons, or settings.
First, clear out your old cache files or use the
Free CCleaner download.
You can also try going into IE Menu, and click
Tools>Internet Options and select the
Advanced tab. Click the
Reset button.
Click
RESET.
Do "NOT" checkmark Delete personal settings. You'll need to re-boot your computer.