IfranView
 

I'm new to frostwire after upgrading from limewire, and back when I had limewire, I could preview most video files with ifranview, however I never knew how I got it to do that in the first place.
Now I really need it to do it for frostwire, but I'm unsure how.

You may need to re-set the default program for video viewing on your system: Setting Default video app :)

Hi, Akeem...

If you are a regular user of Irfan's magic stuff you will be familiar with the way it offers you 'association' selections when you install it.

Perhaps that is all you need to do ?
Be sure to get his latest version, if you don't already have it and, in addition, maybe you need to reinstall the Irfanview Plug-ins pack... There is a newish version of them available now, also...

The above comments are 'to follow' on after taking the advice from LotR...

IrfanView is the photo editing software. IrfanView is provided as freeware, but only for private, non-commercial use.The software is very fast and small compact.Irfanview to handle a wide variety of graphic file formats.