My computer gives me the message "invalid Menu Handle" when I try and download Something. It only happens when I download RAR files. I have Winrar but to my surprise it was deleted off my PC. I don't know how...

Can someone help me.

Try reinstalling Winrar

Here is a link to a free unrar app
Unrar with RarZilla Free Unrar 2.55, Download for Windows (Freeware, Tool) (http://www.philipp-winterberg.com/software/rarzilla_free_unrar.php)

Try reinstalling Winrar
I also agree with you, try reinstalling

You should try reinstalling is my opinion also