There is not enough information in your post.
- Provide a link to the 'broncos wallpaper' in your post. Is this a Google Play app or did you side load it?
- 'got a message to scan for virus', are you saying that you have some sort of anti virus software on your evo? If so, which one?
- Did you open the app at all, or did you uninstall it immediately like you said? Market apps cant do anything unless you give them permissions and open them.
The orange thing to me sounds like you did open the app and it attempted to "theme" your evo to some ugly Broncos colors