We normally recommend these players which both have in-built codecs; VLC - (click on link) _ (choose nearest mirror site) OR/And find the MPlayer link & other things here CODECs list and alternate players for Movies

Also see these 1. **BEWARE** - Download p2p Clients ONLY Thru Official Sites (click on link) & also this one & see if you can recognise the site you got it from 2. Known Scam Sites (click on link)