If they show up as ZIP files, make sure you scan them with your Anti Virus program. I'd be highly suspicious of them. Remember videos should be many MB's in size, & audio files should be a couple of MB's at least. Take a look at these tips:
Movie download issues (click on blue link) (2nd last post has information on best video formats.) & also
Virus thread: Typical virus spam file sizes - Make a note of them (click on blue link to see). Learn to recognise those file sizes so you can side-step them.
Your welcome.