Pasting html used to work from specific site, no longer works

I have been using a service that provides html code to paste into a post. It always worked, until I had a virus problem last week, now it no longer works. The virus has been removed, and the problem exists on all 3 of my computers. It works from other users, just not the admin (me). Any suggestions? Im not a techie btw, so please be nice and speak down to me…Thanks