Encountered error when opening IE7

Hello,
I was trying to open IE 7 when an error message said that the application was not valid.
I have been using it since and wondered why this error suddenly popped up.
I am used to IE and don’t want to use any other browser.
Any advice on how to resolve the issue?
See below the error message I got.

Windows
Internet Explorer is not a valid win32 application.
