Videos with viruses?! You must be refering to WMV right! This is an interesting read & it applies to wmv files also: What you should know about WMA Files

These will definitely help you:
1. Movie download issues

2. Learn to use Bitzi Web Lookup ... & apply it to video files you want info about to see if it's ok. You can also search their database to find info about what you're after. (Unfortunately however, the magnet links shown at Bitzi are not all LW compatible or are out of date.)