Outdated Oleaut32.DLL file

Hi Gang, for no reason all of a sudden I started to get an error message stating;
Microsoft Excel requires file oleaut32.DLL to run. The version of Oleaut32.DLL that is on your computer is older than the one required by this version of microsoft excel. Please run setup again,and select the Reinstall option to install the correct version of the file.

How did this happen? Can I download a new version of this file from internet web sites and how do I insatll it properly?